The Urbanization of Northern Italy: Contextualizing Early Settlement Nucleation in the Po Valley

Recent excavations and theoretical advances have revealed evidence of an early and perhaps independent nucleation and centralization process in the region south of the Alps, a phenomenon that has been undervalued in previous studies. In this paper I present a broad overview and attempt to reassess the role of the Cisalpine regions as crossroads of trade and cultural transfer between the Mediterranean and central Europe through a critical evaluation of key archaeological evidence. I adopt alternative and up-to-date perspectives on the urbanization phenomenon, disentangling commonsensical and text-driven definitions of urbanism and social formation, while challenging the outdated “check-list” approach. This theoretical framework should promote a paradigm shift that leads to a substantial backdating and broadening of the appearance of complex site agglomerations in northern Italy, avoiding unidirectional development patterns and instead looking at possible cases of instability, ephemerality, and seasonality. The adoption of a comparative perspective triggers a timely disentanglement of the simplistic equation between urbanism and social hierarchy. Beyond a narrow and selective emphasis on elites, this paper considers alternative social entities and actions, including commoners, subaltern groups, and cooperation.


Introduction
This paper sketches the process of centralization and settlement nucleation that took place in the Po Plain of northern Italy between the Late Bronze Age and the first half of the first millennium BC. I assume that societal change and settlement reorganization were ongoing in diverse Mediterranean and European regions during this period. However, although the picture of central Europe has radically changed in the last two decades thanks to extensive research projects and game-changing interpretations (Brun and Chaume 2013;Fernández-Götz 2018;Fernández-Götz and Krausse 2013;Fernández-Götz et al. 2014;Krausse et al. 2016;Sievers and Schönfelder 2012;Stoddart 2017), and while urbanism has been a primary topic in Etruria and Latium (Attema et al. 2016;Fulminante 2014;Guidi 2010;Leighton 2013;Pacciarelli 2001Pacciarelli , 2010Riva 2011Riva , 2015Robinson 2014;Stoddart 2016), the role of northern Italy has remained rather overshadowed (Govi 2014;Pearce 1998;Piana Agostinetti 2012;Smith 2017). This underrepresentation has multiple causes, too many to be listed here. One might mention only that local study traditions have remained fragmented between the boundaries of different disciplines and approaches, namely protohistory, Etruscology, and classical archaeology (Vanzetti 2002), and that the scarcity of published data and the limited scope of research projects have also played major roles. Nevertheless, the substantial influence of north Italian models on the emergence of complex settlements in temperate Europe has already been hinted at (Collis 2016;Ralston 2010).
My first aim in this paper is thus to provide an updated and more dynamic picture of south Alpine population patterns based on the results of recent archaeological research. The focus is mainly on the alluvial Po Plain, while the cultures and settlements of the Alpine and Apennine regions are set aside or briefly mentioned. The chronological framework considered comprises the late stage of the Bronze Age and the first half of the Early Iron Age (around 1150 to 450 BC). Notwithstanding the considerable debate about Italian Iron Age chronologies-and the different positions held by scholars (Bartoloni and Delpino 2005) caused by the uneven quality of absolute dates and their evaluation (David-Elbiali 2013;Pare 2008), the presence of the "Hallstatt plateau" in the radiocarbon curve, and a number of issues related to cross-dating and chrono-typological methods (de Marinis 2001(de Marinis , 2005(de Marinis , 2014-in this paper I follow a conventional chronological scheme for northern Italy (Fig. 1): Final Bronze Age between 1150 and 910 BC (the "low" dating parallels the Hallstatt B2-B3 transition in central Europe, see Pare 2008); Early Iron Age between 910 and 600/575 BC; Middle Iron Age (or Archaic period) between 600/575 and 475/450 BC; Second, or Late, Iron Age between 475/450 BC and the later historical Roman conquest of Cisalpine Gaul (late third/second centuries BC).

Reframing Urbanism
The title of this article should perhaps have ended with a question mark. Can we speak of "urbanization" in northern Italy before the classical and Roman periods? This doubt prompts other conceptual questions: What is urbanism in archaeological terms? Is it still a useful heuristic category? How can we identify, without the support of written and epigraphical sources-as is the case for Bronze and Iron Age northern Italy-a self-perceived sense of "urban" lifestyle, if any? Are there more it seems difficult to identify an emic perception of what was believed to be part of a civitas (for example), likewise with classical historical and archaeological study traditions mainly focused on the Greek-derived idea of polis (Ampolo 1988;Hall 2007;Osborne 2019;Riva 2020).
In Italian protohistoric study traditions, the primitivist, diffusionist, and linearevolution perspectives have led to the use of awkward terms like "proto-urban" (see also Moore 2017;Smith 2016, p. 158), which appears to be a definition based on vague criteria that seemed helpful only to justify the presence of centralized, complex sites before exposure to some external supposed influence (here, Greece, Etruria, or Rome), or before reaching a completely "urban" stage, whatever that means (Riva 2015, p. 440). "Central place," on the other hand, is a general label that could refer to ''any kind of place with central functions for a supra-local community'' (Gerritsen and Roymans 2006, p. 255; see also Fernández-Götz 2018, p. 119)-a term that looks too unspecific to explain the multifaceted nature of the archaeological evidence described below.
The much-debated category of "state" itself, namely a regionally organized society ruled by ranked classes, with highly centralized and internally specialized government (Jennings and Earle 2016;Scott 2017) that conducts coercive tax collection (Scott 1998), albeit adopted in previous regional studies (Guidi 2008(Guidi , 2010, appears not always adequate since it derives from the colonial context (McIntosh 1995;Moore 2017). Moreover, the limited archaeological evidence regarding Bronze and Iron Age northern Italy does not enable an understanding of the structure of any administrative governments or political institutions, or indeed the precise extension of ruled territories.
Finally, we must ask ourselves if too much emphasis has been put on urbanism itself in archaeological discourse; after all, more recently there has been a trend toward alternatives to urbanism (Gaydarska 2016;Moore 2017), exploring more nuanced categories such as nucleation, or population aggregation (Gyucha 2019;Riva 2020). The main focus of a comparative approach is therefore on the variety and adaptive forms of settlement agglomerations, for which the traditional definition of urbanism is not well suited. There are many more possible interpretations of manifestations of "urbanism," including "mega-sites" (Gaydarska 2019), "low-density" occupation (Fletcher 2012), and temporary meeting places (Fernández-Götz 2018;Moore 2017), along with small-scale and densely populated trading centers. Some examples of these alternative scenarios are described in the paragraphs below.
Although focusing on labels to describe the archaeological record is somewhat unavoidable, we should not, however, be obsessed by urbanism as a comprehensive and unidirectional heuristic category. It is far more important to describe and explain the various data available from a certain region, addressing multiple factors from a flexible perspective and avoiding socioevolutionary classifications. In fact, too narrow a terminological debate on what can be called "urban" or not might overshadow our understanding of the complexity of the societies studied (Moore 2017). Conversely, it is difficult to deny that urbanism still exercises a certain allure, which, if used consciously, could be useful to attract the attention of specialists and the wider public and reemphasize the significance of some overlooked sites or regions (see criticism in Moore 2017). Journal of Archaeological Research (2021) 29:387-430 In what follows, I introduce a selection of cultural traits derived from the widerranging reappraisals of ancient urbanism (Marcus and Sabloff 2008), although remaining distant from a "checklist approach" that is the search for a site's urban characteristics in relation to a supposed "standard" model of the classical city, a method traditionally adopted in archaeological urbanism after Weber (1966Weber ( [1921), Wirth (1938), Childe (1950), Braudel (1976), and Kolb (1984) (see criticism in Fernández-Götz 2018;Jennings and Earle 2016;Mogren 2016;Moore 2017). Comparative (Feinman 2018;Smith 2012) and qualitative (Mogren 2016) frameworks seem instead more useful to unravel the massive changes that occurred in Po Valley societies between the end of the second and first part of the first millennium BC.
In accordance with this premise, for a discussion of pre-Roman settlement aggregations in northern Italy, I organize the paper around a selection of distinctive and unprecedented context-specific attributes in sections that cover trade and longdistance contact, the presence of connective infrastructures, site scale and layout, enclosures and defenses, public spaces, settlement planning and building technology, settlement hierarchy, population growth, and social stratification.
The psychological and symbolic attractiveness of the centralized site, however perceived and (self)promoted, could also be assumed, although this is more difficult to demonstrate in preliterate societies. The presence of ancestrally significant places, somehow exploited for communal cultural memory (Moore 2017), should also be considered with regard to settlement choice and further development.
In addition, it is worth remembering that "all that glitters is not gold," and negative effects of urban living should also be taken into account (McMahon 2020). In social studies, cities and towns are indeed considered as vectors of overexploitation of natural resources, social inequality and social conflicts, crowding, poverty, and disease (Algaze 2018;McMahon 2020;Scott 2017).

Missing Urban Attributes
Other categories derived from the traditional checklist approach and associated with the "urban versus nonurban" debate are underrepresented in the studied region. These missing features are mainly monumental architecture, including royal palaces and large temples, long-lasting stone buildings, and (textual) evidence of administrative bodies. This could, of course, depend on investigation strategies and archaeological visibility, but we cannot exclude that some of these traits were simply not relevant to the local societies (Smith 2016, p. 164) or not adaptable to the regional environment.
Before the introduction of written history in the Greek and Roman periods, other categories of information seem not easily accessible, such as discourse on legal status (citizenship). In addition, in the study region, there were not even mints or coinage before Roman influence and conquest, and for centuries the exchange model remained based on nonmonetary mechanisms. Another factor that hampers our understanding of centralized sites in northern Italy is settlement duration. A specific condition of several towns in the Italian Peninsula is their long-term human habitation through the millennia, which often limits the use of geophysical methods and extensive excavation projects. With the few exceptions of sites without later occupation layers (such as Spina and Forcello, among other sites described in the following paragraphs), reconstructions are mainly based on preventive surveys and small trench excavations, often subject to the limitations of urban archaeology.

Environmental Setting: Between the Alps and the Apennines
The Po Valley, the largest floodplain in Italy, more than 71,000 km 2 (see Brandolini and Carrer 2020), is a typical river valley with abundant land and water resources, the kind of environment that worldwide is usually characterized by intensive resource exploitation, demographic growth, and settlement aggregation (Carneiro 1970;Feinman 2018). The region is situated between two major mountain ranges, the Alps and the Apennines, and is crossed from west to east by a principal river, the Po, and by the River Adige in the north-eastern sector, together with several tributaries and secondary streams (Fig. 2). Lakes and perifluvial water basins are also preeminent features, as are swamps and coastal lakes in the delta area (Balista 2018;Ravazzi et al. 2013). Adaptive strategies across the millennia have usually focused on river terraces and proximity to active waterways.
On one hand, this environment provides soil fertility and good connectivity based on river transport, but on the other hand, it constitutes an unstable landscape, subject to floods, frequent overflowing, and river diversions, especially during periods of worsening climate (Cremaschi et al. 2016). Consequently, great efforts have always been made in these regions regarding water management, hydraulic technology, and drainage works Ortalli 2010), including embankments, moats, ditches, canals, and field channels. How these conditions may have influenced the size and layout of Late Bronze and Iron Age settlements is outlined in the following paragraphs. In addition, the abundance of water represents an extremely favorable environment for archaeological research, accounting for the exceptional state of preservation of perishable materials including timber, wooden artifacts, and textiles.

Trade and Long-Distance Contact
The first attribute I explore regards production and trade, since the economic processes of production and redistribution are usually considered an important force leading to settlement nucleation and agglomeration. These activities have indeed been hallmarks of the Po Valley through the millennia, thanks to the availability of natural resources and its strategic position. The importance of interdependence and growing economic networks in the Po Valley in the Late Bronze and Iron Age is clearly shown by the archaeological evidence, together with certain specific trajectories and local developments that are well-illustrated by a selection of comparable cases-Late Bronze Age polities and the hub of Spina. What stands out is a general trend toward the formation of focal centers of economic and political networks, as well as a labor-intensive engineered landscape.
In the Middle and Recent Bronze Age (from around 1650 to 1150 BC), the Terramare culture flourished in the central Po Valley. This society established long-term trade and connections with central and northern Europe and the Mediterranean, with an economy based on the exchange of raw and semifinished materials, including grain and animal products, in addition to textiles and bronze weapons, utensils, and ornaments (Kristiansen 2018). However, after a general crisis toward the end of the Recent Bronze Age (1200/1150 BC), the Terramare system collapsed (Cardarelli 2009;Cremaschi 2009;Cremaschi et al. 2006). A combination of factors has been invoked for the complete abandonment of the Terramare culture, including demographic pressure, political instability and warfare, overexploitation of resources, and consecutive years of drought as triggering events (Cardarelli 2009;Cremaschi et al. 2006Cremaschi et al. , 2016; see also Kristiansen 2018 for a broader picture of international Bronze Age connections). Only in western Veneto, within the "Valli Grandi Veronesi" polity and the central place of Fondo Paviani (Cupitò et al. 2015), was the Recent Bronze Age crisis somehow less severe.
During the following Final Bronze Age, the settlement of Frattesina some 50 km farther south (Bietti Sestieri et al. 2015) managed an international trade in raw and partially worked goods, such as amber, ivory, bronze, and glass (Bietti Sestieri et al. 2019). Frattesina was the focal center of a settlement polity in the Polesine region, which comprised the nearby large settlement of Villamarzana (Salzani and Consonni 2005) and the craftworking site of Campestrin di Grignano Polesine, where amber beads were produced at a large scale during the 13th century BC, including "Tyrins type" beads, which also are widespread in the Aegean and the Levant 1 3 Pearce 2019). Frattesina is interpreted as the hub of an international exchange network, involving the northern Adriatic region, central Europe, and the Aegean world, with trade based mainly on prestige and exotic goods, such as amber, elephant ivory, and glass (Bietti Sestieri et al. 2019;Cardarelli et al. 2015). Regarding glass production, there is evidence of a local workshop in Frattesina, including crucible fragments, glass ingots, and waste from the working of some 2,800 beads. According to element and isotope analysis, mixed-alkali glass (referred to as LMHK, low magnesia and high potassium oxide) was produced in Frattesina Pearce 2019). The isotopic origin of the copper has been recognized in Trentino-Alto Adige, one of the most important European protohistoric mining districts (Bietti Sestieri et al. 2019).
Continuity in the flow of goods and long-term connectivity are evident through the early centuries of the first millennium BC. While there was a shift toward new centers of power and trading hubs, like Este and Padua in the Veneto, and Verucchio and Bologna in the south and southeastern areas, no general crisis or depopulation affected northern Italy in the following centuries, until the fifth century BC at least.
Conversely, in connection with the "globalization" of Mediterranean trade (Sherratt 2016), the Po Valley experienced a trade explosion, with the opening of new markets and the strengthening of contacts and exchange with both the Mediterranean and central Europe (Collis 1997;Sassatelli 2011). Especially after the midsixth century BC, there was a detectable increase in the presence of Greek trade along the Adriatic, and the local communities welcomed these new commercial opportunities by opening emporia, such as Adria and Spina.
Spina, in particular, demonstrates the scale of international trade during the Middle Iron Age, as shown by the amount of imported Greek pottery (black and red figured, black glazed), oil and wine amphorae (Sacchetti 2012), as well as bronze, glass, and amber artifacts (Zamboni 2016). Other exotic products include oil, unguents, perfumes, spices, and various wines that came from the Aegean, eastern Greece, and Egypt, as indicated by the presence of characteristic vessels and amphorae (Sacchetti 2012). Imported for centuries from the Baltic regions into the northern Adriatic area, amber was worked or partially worked and redistributed from Frattesina in the Final Bronze Age, from Verucchio during the ninth and seventh centuries BC, and finally from Spina after the mid-sixth century BC.
Another detail explains, more than others, the level of cultural interaction in Spina: the arrival of the complete set of Greek cooking ware (kados, chytra, kakkabe, lopas, and mortarium); these vessels coexisted with the local wheel-turned and handmade coarse-ware ollae and pots, which documents the ongoing process of cultural hybridization within the social space of the kitchen (Mistireki 2019;Zamboni 2017b). Trading routes to other regions of northern Italy and central Europe are also traceable in the distribution of settlements and imported goods all across the Po Valley. Intermediary outposts were founded along the course of the Po River and its tributaries, like the emporion of Forcello di Bagnolo San Vito (see below).
Through the ages the plain has been a core agricultural area able to exchange an abundance of trade goods, including cereals, meat, salt, and craft materials. Exports consisted mainly of agricultural products, especially wheat. Focusing again on Spina, thriving agricultural production and consumption has been revealed by palaeobotanical analysis, which has documented the presence of chard, lettuce, fennel, dill, carrot, and parsnip (see Marchesini and Marvelli 2017) among the vegetables. The daily diet in Spina was also based on barley, bread wheat, spelt, millet, legumes, beans, peas, chickpeas, lentils, and aromatic plants such as rosemary, sage, and mint. Dried and fresh fruit were available and consumed (hazelnuts, walnuts, pine nuts, cherries, grapes, plums, and even melon), and olives and vines were cultivated locally (Marchesini and Marvelli 2017, p. 50). Moreover, the plain and the nearby woodlands provided reeds, skins, worked animal bone and meat, especially of pigs, along with fishing (Trentacoste 2016).
Another long-term activity along the Adriatic coast was the extraction of salt from seawater, fundamental in farming and the dairy industry, for food preservation and for tanning clothes (Harding 2013), and it likely used as "commoditymoney" (Zamboni in press a). Some ancient authors also mention a further aspect of Iron Age commerce, that is slavery, which, however, leaves few or nearly invisible archaeological traces.

Trading System and Standardization
Protohistoric transactions were based on a specialized form of barter that involved standardized ponderal weighing systems and proto-currencies; substantial coinage was absent until the Late Iron Age (Zamboni in press a). In this region, as well as north of the Alps, a long-term tradition of regularized barter, based on relatively accurate weighing systems, was present from the Bronze Age (Ialongo 2018;Rahmstorf and Stratford 2019). After the Terramare era, when this system was developed, similar regular stone and lead weights were adopted by the Frattesina polity and other Final Bronze Age cultures.
During the Iron Age commodification of several noncountable goods and raw materials, including salt, grain, and meat, was made possible by the adoption of a similar system based on stone or metal weights and equal-arm balances, which make use of different weight units and compatible multiples and fractions (Zamboni in press a). The use of "utensil-money," like silver and other valuable goods, is also assumed (Vickers 2017) but more difficult to prove because of its low archaeological visibility. Moreover, the presence of aes rude, including a special thin type of token known from the main emporia of the late sixth and fifth centuries BC (Spina, Adria, Oppeano, and others), and aes signatum, starting from the fifth century BC, in several sites supports the use of proto-currency. However, it remains unclear whether the aes tokens were employed only as objects of known weight (per aes et libram), or perhaps they had a value assigned by some authorities (see Zamboni in press a). Although in small quantities, actual coinage began to circulate in northern Italy only after the Gallic invasion and the beginning of the Roman conquest (Gorini 2017; Zamboni in press a).
How do we interpret this commodification tradition and standardization process in the Po Valley over the longue durée? The broader archaeological picture suggests that it is unlikely to have been due to some sort of superregional ruling authority or "state" (see below); more probably it was associated with the persistence of successful self-regulated trading networks based on customary commercial relationships that fostered mutual interaction and the possibility of normalization and conversion between different commodification systems (Ialongo 2018; Zamboni in press a).

Connections and Infrastructures
A large-scale exchange economy is made possible and promoted by an adequate network of natural and artificial infrastructure. Among the first, it has frequently been claimed that northern Italy shows strong transalpine connections since prehistory (Barfield 1971;Deschamps et al. 2019;Pauli 1991;Pearce 1995), since the Alps do not seem to have been a major obstacle to ancient mobility, as might have been expected. To the south, conversely, the Apennine mountains, although of lower altitude, have often been described as less permeable, with few passes and straight crossings (Pearce 1995; for a different perspective see Locatelli 2014;Santocchini Gerg 2015). Boats could dock both on the Adriatic shore (at Rimini, Spina, San Basilio, Altino) and the Tyrrhenian side (at Chiavari, Genoa, Savona). The main Iron Age lines of transport are assumed to have been the rivers and streams, navigable with small boats since prehistoric times Pearce 1995), as no out-of-town paved or unpaved roads of pre-classical date have been discovered. The waterways connected the Po Valley southward to the Apennines and northward to the principal Alpine passes of Brenner, Stelvio, Splügen, St. Gotthard, St. Bernard, among others (Fig. 2). Of course, terrestrial paths also were possible, albeit they are more difficult to identify (Pearce 1995). For example, cross-country pathways were in use along the Apennine foothills (becoming the Via Aemilia after the Roman conquest) or farther north connecting Lake Garda, the Golasecca domain, and the Alpine passes (Cicolani and Huet 2019).
The presence of engineered connecting structures is somehow less visible. In the Iron Age some extra-urban paved routes are found outside the major centralized sites, such as Bologna and Este, while fords and seaports are even more elusive. A major ford on the River Po is assumed to have existed near Brescello, province of Reggio Emilia (see Zamboni 2018b), and in the Golasecca district a river port at Sesto Calende (Via Marconi) is reported to have been active during the fifth century BC (de Marinis 2001). Furthermore, possible seaports on the northern Adriatic shores are Altino, already established between the ninth and eighth centuries BC (Tirelli 2011), and to the south in possible connection with Adria, San Basilio di Ariano Polesine (Salzani and Vitali 2002), where preliminary excavations have yielded high-quality Greek pottery, mainly dating to the sixth century BC (De Min 1988).

Site Scale and Layout
Analysis of settlement sizes, mainly determined by the identification of boundaries and defensive elements such as ramparts, moats, walls, or canals, is common practice in archaeological urban studies. According to the traditional checklist approach, a "town" should possess a large, dense population aggregated inside a nucleated and structured settlement. The estimated size of urban settlements, however, still remains a controversial point (Mogren 2016). The large scale of settlement areas has often been assumed to be a self-evident indication of centralization and urbanism. Yet a polythetic interpretation model claims that settlement size and population size per se do not really matter, as "sizes of early urban agglomerations were far from uniform" across world cultures (Feinman 2018, p. 15). It should also be recognized that a site's maximum extension need not be merely determined by natural borders (hillsides, high ground, or rivers), rather estimates ought to be based instead on a careful and diachronic evaluation of landmarks, including defensive structures and lines of enclosure, suburban cemeteries, extra moenia cultic places, and extra-urban roads (Gamba et al. 2008;Rondini and Zamboni 2020a). Unfortunately, extensive and intensive "big data" projects, which combine high-resolution remote sensing and geophysical surveys, are not yet available in the study region. A close look at selected sites from the Po Valley between the Late Bronze and Early Iron Age, however, helps clarify the role of site scale and settlement layout seen through the lens of a context-based approach.

Bronze Age Agglomerations
The first known structured sites in the Bronze Age are related to the Terramare culture. The Terramare were high-density square settlements, between 2 and 20 ha in area, surrounded by ditches and ramparts, with houses built on piles and advanced water-management systems (Bernabò Brea et al. 1997;Mele et al. 2013).
In the last stage of the second millennium BC, the leading settlement of Frattesina (which is only partially known) appears to have occupied an elliptical area of around 12-20 ha, oriented east-west along the ancient course of the Po di Adria, a northern branch that has now disappeared. Major features in Frattesina are the presence of a grid of perpendicular canals around a main central axis, probably a large canal, along with other drainage works that define the settlement area (Bietti Sestieri et al. 2019).
The Frattesina polity network was not isolated in the context of Final Bronze Age northeastern Italy. Another relevant site is Montagnana, only 30 km northwest of Frattesina, where there was a settlement covering 14 ha surrounded by wooden palisades in the mid-10th century BC. An overall size of 65 ha was reached by Montagnana between the late 10th and ninth centuries BC . Other early structured sites in eastern Veneto were Treviso and Oderzo (Capuis and Gambacurta 2015).

Early Iron Age Nucleation in Northeastern Italy
At the turn of the millennium a process of diffuse settlement nucleation was underway, mainly in the regions closer to the Alps. These habitations expanded rapidly, with dimensions ranging from medium size, around 25-80 ha, to larger sites of up to 100 ha (Capuis and Gambacurta 2015). The selected locations were on flat river terraces raised over the surrounding wetlands and woodlands, often at the confluence of two or more rivers. In Veneto, a series of endogenous factors may be envisaged for the process of early nucleation, including demographic growth and an increasing intensification of production, with episodes of continuity and settlement expansion from the preceding Final Bronze Age, the abandonment of previous sites, as in the case of Frattesina, and the foundation of new centers.
The new town of Este became the focal point of the Veneto Iron Age culture. The settlement was founded after the abandonment of previous Final Bronze Age dwellings in the southern terrace of Borgo Canavero (Bianchin Citton 2015), possibly in connection with the decline of Montagnana, 16 km to the west. Already in its early stage, the nucleation process in Este led to a size of some 100 ha ( Fig. 3) (Capuis and Gambacurta 2015), with an engineered environment documented by drainage, wooden planking, and platforms.
A second center of remarkable size, Padua, was founded about 30 km northeast of Este, strategically located on the banks of the Brenta River (Medoacus in Latin), a waterway connecting the circum-Alpine region to the Venice lagoon. After Late Bronze Age dwellings, a large structured settlement was established before the end of the ninth century BC, with an overall area of 120 ha in the eighth century BC (De Min et al. 2005).
Two other large, structured settlements-Oppeano and Gazzo Veronese-were established in the western Veneto Plain during the early Iron Age, sited on main routes towards the Adige River and Lake Garda. Inhabited since the Final Bronze Age, the ancient river terrace town of Oppeano reached an extension of 80 ha in the early Iron Age (Fig. 3) (Candelato et al. 2015), with productive districts, storage facilities, and cultic places documented during recent excavations. The southern side of the settlement had been reinforced by a ditch and rampart (Balista 2004).
Gazzo Veronese is the westernmost site in the Veneto Plain, at the confluence of the Tartaro and Tione Rivers. The upper terrace of Coazze, of around 30 ha, had been populated since the Final Bronze Age, and the whole settlement extended over an area of nearly 60 ha, at least during the sixth century BC . In the easternmost part of northern Italy, in the present-day eastern Veneto and Friuli regions, the archaeological evidence points to a different occupation pattern, with a dense network of small or medium-size fortified settlements (or castellieri), such as Concordia Sagittaria, Palse, Gradisca, and Pozzuolo, which however never reached the large dimensions and structural complexity of the western Veneto sites (Borgna et al 2018;Prosdocimi 2017   northwestern part of the Po Valley presents a somewhat different picture. The alluvial plain remained largely untouched, and the major agglomerations were located in the Alpine foothills. Here, in present-day eastern Lombardy, western Piedmont, and the Ticino region of southern Switzerland, after prior Final Bronze Age occupation (Protogolasecca period), the dominant Early Iron Age phenomenon was the Golasecca culture, mainly defined on the basis of funerary evidence (de Marinis 2001;de Marinis and Biaggio Simona 2000;Lorre and Cicolani 2009).
An early settlement aggregation is located between the modern villages of Castelletto Ticino, Sesto Calende, and Golasecca. The site was on the river terraces where the Ticino crosses Lake Maggiore, along one of the principal pathways to central Europe. A ninth century BC cemetery is known in Via del Maneggio, but a larger settlement was established nearby between the eighth and seventh centuries BC (Fig. 3). Although no enclosure has been yet identified, the estimated area is around 90 ha (Gambari and Cerri 2011). The amount of imported goods from the cemeteries testifies to a wide range of connections, from central Italy to the Hallstatt regions (Casini 2015;Cicolani and Huet 2019). In the Middle Iron Age, however, Castelletto declined and was abandoned in about 475 BC, probably after deterioration of the climate and local environment, and at the same time a second Golasecca center emerged at Como.
Como was established on the hill of Monte della Croce, at the southern tip of the southwestern arm of Lake Como, overlooking a swamp where later the Roman town was founded. Although already populated in the Late Bronze and Early Iron Ages, Como flourished during the sixth and fifth centuries BC, reaching an extension of some 150 ha (Casini et al. 2001;Mordeglia and Uboldi 2017).
After the foundation of Genoa during the sixth century BC (Melli 2007), the preeminent pathway in the western part of northern Italy become the north-south route connecting the Tyrrhenian Sea to the Alps along the Polcevera, Scrivia, and Ticino Rivers. In southern Piedmont, the productive site of Villa del Foro was active during the sixth and early fifth centuries BC (Venturino et al. 2017), but no other nucleated settlement is known to date. As suggested by Pearce (2007), in peripheral regions such as southern Piedmont, it is possible to see long-term analogies between the absence of Iron Age urbanism and the failure of late Roman and medieval towns, on the basis of similar environmental instability and marginal geographical conditions. In the midwestern Po Plain, the picture changed only during the fifth century, when the center of Milan, the region's capital in the centuries to follow, was established at the confluence of several waterways (Ceresa Mori 2015).

Low-Density Early Urbanism in Northern Italy?
Given the remarkable estimated size reached by some of the major north Italian sites between the 11th and eighth centuries BC, like Villamarzana (65 ha), Montagnana (65 ha), Este (100 ha), Padua (120 ha), Castelletto Ticino (90 ha), and Bologna (180 ha, see below), one may wonder what kind of urbanism we are dealing with. Were these centers densely inhabited from the beginning, after considerable population growth and immigration? Or is it possible to hypothesize the presence of low-density agglomerations? Low-density urbanism is an alternative form to the "classical" model that assumes the existence of multiple agglomerations, or multipolar centers, with a dispersed population. From a comparative perspective, the primary role of low-density urban sites would have been for assemblies and public meetings, rather than for permanent habitation, as in the European examples of the oppida of Manching and Bibracte (Fernández-Götz 2018; Moore 2017), or farther afield in Mesoamerica and Africa (Fletcher 2012). As far as northern Italy is concerned, the identification of low-density agglomeration is limited by the scarcity of evidence regarding clearly defined open spaces for public meetings or assembly.

Palisades and Defenses
Fortifications, in whatever form-ditches, ramparts, walls, and other kind of enclosures-are widespread among human settlements; they may at the same time be a highly visible and problematic proxy in archaeology. As recently argued (Reymann 2020), an emphasis on the category of "fortified" settlements in archaeology may lead to a stereotypical classification of institutionalization and urbanism. The implicit assumption is that only an elite-guided or stratified society would to be able to organize the amount of work required for building massive fortifications (for alternative views on common labor, see Feinman 2017).
Yet a look at the ethnoarchaeological evidence suggests a more cautious and polythetic approach, as there is no clear link between fortification and complex social systems. Consequently, fortifications alone may not be used as self-evident indicators of centralization and urbanism. As Reymann argues (2020, p. 12), "different social systems can construct similar fortifications, so that a fortification itself seems not to reveal what type of social system it was based on." In fact, a number of complex fortifications do exist among hunter-gatherers and in small-scale societies with low social and political complexity, as well as in diverse hierarchical prestate societies.
From this perspective, fortifications are assumed to be mainly signifiers of (expected) forms of warfare, but also, as in the Po Valley, attempts to prevent flooding and other natural calamities. The symbolic meaning of delimitation between "in" and "out" space should also not be underestimated (von Nicolai 2020). On the other hand, during the Early Iron Age, unprecedented massive enclosure works appeared in northern Italy together with further categories of settlement centralization, such as increases in production and trade, site size and hierarchy, and social complexity. We can test this hypothesis at the site of Verucchio.

The Fortifications of Verucchio
Situated in the southeastern sector of present-day Romagna, in the Apennine foothills and close to the Adriatic coast, Verucchio was a powerful center in the ninth to seventh centuries BC (Zamboni 2018a;Zamboni and Rondini 2018). Due to its strategic location, Verucchio could control the mouth of the Marecchia River, at the end of a valley, which rises to the southwest toward the Tiber springs and inland Etruria (Naso et al. 2014).
Recent archaeological investigations carried out on the hilltop of Verucchio, in the Pian del Monte area, discovered a large north-south oriented earthen structure at least 70 m long and 8 m wide, composed of a ditch, two canals, and a timber palisade, documented for a maximum length of 11 m, with posts that were 80 cm wide and 60-70 cm deep on average, located at the bottom of a narrow ditch (Fig. 4.2) (Rondini and Zamboni 2020b;Zamboni and Rondini 2018). Other features on the western side of the main structure, including a water well, minor channels, and several pits, could have served for drainage, water management, and productive activities .
This moat and palisade system could be part of a larger enclosure that surrounded the southeastern hilltop of Monte dei Gigli, already settled during the Final Bronze Age (Bartolo 2018). The fills of the ditch, the canals, the palisade, and the surrounding pits contained local handmade domestic pottery that dates to the early Villanovan period (late ninth-early eighth century BC), as confirmed by radiocarbon determinations (Rondini and Zamboni 2020a). This relatively early date suggests that Verucchio should no longer be considered a "colony," founded by newcomers from mainland Etruria (Guidi 2008;Sassatelli 1996), but rather the result an endogenous agglomeration process.
Moreover, the disuse of the defensive structure suggests a reorganization process after the ninth century that involved the entire hilltop of Verucchio (covering nearly 27 ha, Fig. 3), with new cemeteries, mainly dating to the eighth and seventh centuries, established all around the rocky hillsides (Lippi, Le Pegge, Moroni). Verucchio was suddenly abandoned around the mid-late seventh century BC just after its heyday, when grave goods from the burial grounds indicate that a powerful and wealthy society was present (von Eles 2013). The reasons for this abrupt decline are still unclear, but either the collapse of the aristocratic society or external macroeconomic and political changes can be envisaged.

Other Early Iron Age Fortifications
Wooden enclosures and earthen fortifications are recurrent features in several nucleated centers of the Early Iron Age Po Valley, where they usually were coupled with ditches and canals; in addition to warfare, they may have been constructed to prevent the recurrent and urgent problem of flooding. In Este, for example, there are structures for water management and wooden fences around the perimeter, including an oak timber waterfront of horizontal beams in the southeastern sector, dated by dendrochronology to the end of the ninth century BC (Fig. 4.1; Meadows et al. 2014). In a similar manner, Padua was surrounded by a double wooden palisade, dated to 840 ± 130 BC (Balista and Rinaldi 2005; see also Rondini and Zamboni 2020a).
A massive fortification has been discovered in Bologna, in the northwestern sector of the site in Piazza Azzarita. There, a structure 40 m wide was composed of three parallel ditches in front of a series of aligned timber palisades, each one with at least three rows of large posts, reinforced with wooden planking (the total length is unknown due to the limited size of the excavation trenches). Its boundary role is confirmed by the presence of a cemetery just outside this construction (Ortalli 2018).

Public Spaces
The site of Bologna is also instructive for the presence of a different type of feature, otherwise extremely rare in Iron Age northern Italy, that is open areas for communal meetings. Called Felsina in the Etruscan period, this major site prospered at the foot of the Apennines, controlling a large part of the fertile plain along the Reno River, a major natural route across the mountains to Tuscany. The ancient site is only partially known, due to its burial by deposits that have accumulated continually through the millennia, yet recent rescue excavations unearthed evidence that has been linked to an early and independent nucleation process (Ortalli 2013(Ortalli , 2018. These results suggest that Bologna was founded during the eighth century BC after the abandonment of at least three nearby ninth and mid-eighth century BC villages Ortalli 2018;Vanzini 2018). The new site was at the foot of Villa Cassarini, a high ground with religious or representative role (Ortalli 2013;Santocchini Gerg 2015). A settlement size of at least 180 ha in the early phases has been suggested ( Fig. 3; Ortalli 2010Ortalli , 2013. In the northernmost sector of Piazza VIII Agosto a massive structure about 50 m wide (and investigated for 100 m of its length) was recorded, composed of hundreds of large posts, with postholes more than 1-m deep, aligned north-south in three rows, and spaced 10 m apart (Fig. 4.2; Ortalli 2013). This timber structure was dismantled during the seventh century BC, for reasons probably linked with a reorganization of the town's layout.
In this respect, Bologna might be an example of a "political city" (Smith 2016, p. 165), a large structured and nucleated settlement where public activities took place, involving populations from wider areas. These performances may also have been "theatrical" ceremonies (in accordance with the classical definition of Geertz 1980). As already suggested by Ortalli (2013Ortalli ( , 2018, an open area such as Piazza VIII Agosto could have hosted communal practices and/or rituals and processions, perhaps employing resources coming from the surrounding agrarian landscape (i.e., of "internal" production), social activities that would have taken collective forms (Feinman 2017). The contemporary iconographical representation of aggregation, civic ceremonies, and performative collective meetings in Situla art (Zaghetto 2017) might confirm the cultural importance of these practices in Bolognese as well as Veneto societies.

Regular Plans
A nucleated site of the "urban" type is often defined by the presence of regular planning and formal house building, displaying a relatively high degree of technology and architectural solutions able to ensure their inhabitants live with a certain level of efficiency, and comfort (Braudel 1976;Smith 2007 and. In the Po Valley settlement plans are deeply influenced by the local environment, a palimpsest of water bodies and wetlands, rich in water resources and fertile soil but also unstable and changeable. It is thus probable that structured and organized forms of settlement were perceived as more suitable, together with intensive land management. A local and continuous tradition of regularized sites, with perpendicular grids composed of rectangular units, was present since the Bronze Age Terramare culture (Cardarelli 2018), with continuity through the Final Bronze Age, in sites such as Frattesina, Calcinato (near Brescia), and Treviso (Rondini and Zamboni 2020a), and during the entire Iron Age.
In general terms, a right-angled grid has usually the double aim of giving the settlement a regular form and keeping it cleaner and drier. On the other hand, as argued by Scott (1998), a geometrical and formal urban order is at the same time a powerful administrative tool and a means of social regulation, or even of coercive control. In the Po Valley the perpendicular grid was first created with large or minor canals, instead of paved or unpaved streets. Frattesina had a regular plan of canals during the Final Bronze Age, and these are widespread in most of the Iron Age sites.
What remains unclear, however, is the actual function of these canals. It is usually assumed that they were artificial waterways, for water management and conveyance. Yet we may wonder whether they were constantly full of water throughout the year, and if the larger ones were somehow navigable with small dugouts (as in medieval and modern towns, such as Venice), or perhaps if there was a regulation system with locks of some sort: the canals could at times have been empty, or maintained with low water levels, and filled in case of necessity, such as flooding or high water, preventing overflow into houses and working areas.
In any event, the main settlement axis was usually oriented along the river, or the nearest water body, and enclosed by defensive structures such as wooden palisades and ditches. The cemeteries were usually placed on the opposite side of the river, for both functional and symbolic reasons (Pearce 2006). Sanctuaries and industrial activities, when known, were mainly located in the surroundings, around the site's perimeter. In a few cases, such as Padua, the settlement plan shows two or more divergent grids (Fig. 3), an indication of adaptation to particular environmental conditions and different water flows.

"Economic Cities"
A regular grid of water canals also were present, and better documented, in new trading hubs founded in the second half of the sixth century BC, namely Adria, Spina, and Forcello (Fig. 5), for which a settlement structure based on regular 1 3 rectangular blocks originating from the canal grid is also evident. The function of these new towns was mainly that of emporia (Gailledrat et al. 2018), or "economic cities" (Smith 2016, p. 165), a definition that includes nucleated settlements where the economic activity has a major role and a stronger influence on the growth of other cultural and political fields.
My first example is Adria, situated in a wetland close to the ancient Adriatic coastline, along an old branch of the Po River (known as the Po di Adria) and active until the sixth century BC. Although a previous Middle and Recent Bronze Age settlement has been identified , there is no evidence of continuity into the Iron Age. The layout of Adria is still unclear, since most of the finds come from 19th century discoveries, and the town has been continuously inhabited until today. The location of the cemeteries, along with the scattered remains of the ancient town, point to an extension of nearly 12 ha. The settlement was oriented northeast-southwest, along the ancient river course, and based on a grid of perpendicular canals. The site's foundation dates to around the second half of the sixth century BC (Bonomi and Gambacurta 2017). Excavations in the 1930s in the Pubblico Giardino area (see Donati and Parrini 1999), and more recent trenches at Ex Riformati (see Bonomi and Gambacurta 2017) have documented foundation drainage layers made of wooden planking and branches.
In addition to Adria, Spina is thought to have been a major international hub in the north Adriatic between the late sixth and fourth centuries BC, a bridgehead of Greek interests toward central Europe (Berti and Harari 2004;Zamboni 2016). Hidden for 2000 years under the mud of the Po lagoon, the first graves were discovered during land reclamation in 1922, with grave assemblages full of Greek pottery, bronze artifacts, small glass and amber objects, and wooden furniture. The area of the site is waterlogged due to its position close to the Po Delta, inside a swamp reclaimed only during the 1950s, and the archaeological features are c. 4 m below current sea level (Zamboni 2017a). Spina was founded in around 540/530 BC, a few kilometers north of a previous Iron Age settlement in the Mezzano Valley-Podere Alberi-which was excavated in the 1980s but is still poorly known (see Cattani and Boccuccia 2018). An ancient branch of the Po River (the Po di Spina) ran on the left side of the town. Across the river, on the sandbanks in front of the ancient seashore, are more than 4,000 graves that have yielded one of the richest collections of Greek vases ever found in situ. A wooden palisade, with six to eight rows of posts and a ditch (Buoite et al. in press) enclosed an area of around 6 ha ( Fig. 6.1). Spina's town plan is regular and oriented north-northeast by south-southwest, with a perpendicular grid of larger and smaller canals defining several rectangular blocks. Spina went into crisis during the mid-fourth century BC; sling bullets and burnt layers probably linked to a military attack have been found at the site (Buoite et al. in press). However, archaeological evidence suggests that Spina somehow survived that crisis, at least until the third century BC (Reusser 2017), when the site was completely abandoned, except for later Roman rural villae in the surrounding area.
A third emporion, Forcello di Bagnolo San Vito, could be interpreted as an intermediary outpost. The site of around 12 ha was settled in about 540 BC on a low ridge along the Mincio River close to its confluence with the Po, a few kilometers southeast of the later town of Mantua (de Marinis 2010;de Marinis and Rapi 2007). Forcello was a harbor on the shore of a lake that has since disappeared (Ravazzi et al. 2013). It played a bridgehead role for the trading of Mediterranean imports to transalpine regions, as indicated by the presence of large quantities of Greek amphorae (Sacchetti 2012), glazed and figured Attic pottery, glass aryballoi and beads, silver and even coral jewelry, along with bronze fibulae of circum-Alpine origin (de Marinis 2014;de Marinis et al. 2017, de Marinis andRapi 2007). Forcello was suddenly abandoned around 390 BC, at the time of the Gallic invasion of Italy.
Another interface area is about 16 km northeast of Forcello, in Gazzo Veronese, at the western margins of Venetic culture. The dynamic role of this site is highlighted by assemblages containing hybrid and culturally mixed elements, including anthropomorphic stone statues (Gamba and Gambacurta 2011) and a variant of redand-black painted pottery (Saccoccio 2016, pp. 253-256).

House Types
Regarding the built environment, another dubious "common-sense" equation in archaeology is between rectangular structures, urbanism, and increasing social complexity, assuming that the discovery of buildings with square or regular plans and multiple rooms is evidence of urbanization. Cross-cultural studies suggest the rejection of such a linear, socioevolutionary view in favor of a higher degree of complexity, with rectangular and square structures documented among nonurban societies (Ember 2014). Once again, only a context-based approach and the recurrence of significant cultural and social features could explain the significance of these findings.
In the Po Valley, rectangular buildings of different size and complexity are widespread from the Bronze Age Terramare culture onward, mainly built on wooden platforms and up to 60 m 2 in area (Cardarelli 2018). In the Early Iron Age centralized settlements at Este and Padua, the houses were rectangular in plan, with foundation beams, clay floors, and daub walls. A similar architectural tradition was present in the sixth and fifth century BC emporia. In Adria, for example, the buildings were rectangular, with horizontal timber foundations protected by covering clay slabs (also known in Spina), walls made of wattle and daub or mudbricks (Bonomi and Gambacurta 2017).
In the earlier phases, the rectangular houses in Spina also were built on interlocking beams (Zamboni 2017a). The walls were made of wattle and daub, occasionally with mudbricks ( Fig. 6.3), without clear evidence of tile roofs until the later phases (fourth and early third century BC), except for a few ridge tiles. In Spina and Adria, it also is common to find rows of posts reinforcing the surrounding canals and the perimeters of buildings.
The rectangular houses of Adria, Spina, and Forcello were of regular dimensions, 17 m long by 10 m wide, suggesting a possible standardized "module" perhaps related to multiples of the "Attic foot" of 29.6 cm (Quirino 2012 andZamboni 2017a). In the western region characterized by the Golasecca culture, square houses with foundations cut into the rock and timber-framed walls are known in Como (Rondineto, Prestino, Pianvalle) and Castelletto Ticino, where regular buildings were made in the earlier periods, with timber foundations and mud walls.

Building Durability
The increasing adoption of stone and brick as building materials in the "classical" cities suggests that durability may be a key element in defining urbanism as a major improvement in lifestyle conditions. This aesthetic and qualitative Western prejudice originated in classical antiquity and increased during the Renaissance and the Industrial Revolution (Braudel 1973;Merlo 1989). Yet, from a comparative perspective, durability appears to be another unreliable criterion, since it depends on the variability of the local environment and the natural resources available, as well as on cultural choices and architectural energetics (Purcell 2005;Riva 2020). The lifespan of wooden constructions is specifically affected by multiple factors, including the type of wood, the time of felling, the use of scorching, the presence of clay daub, and position inside the structure, as well as specific soil, environmental, and weather conditions. Ethnological comparisons point to an average lifespan of earthfast wooden posts between 5 and 9 years, while oak and chestnut beams, in certain conditions, could last for 60 years or more (Črešnar 2007).
Several places in the Po Valley, Spina above all, document the stratification of layers related to burning, collapse, and flooding, with levelling and rebuilding recurring almost every generation (Reusser 2017;Zamboni 2017a). These episodes of instability could be explained by the background of ecological fragility that characterized the waterscapes of the Po Valley, which required continuous effort in land reclamation and maintenance works.

Rural Sites and Hinterlands
Population aggregation in specific places is possible only in relation to a wider landscape, and a hierarchical relationship is usually assumed between the urbanlike centers and rural or minor settlements. We have already stressed how soil fertility and the abundance of water and other natural resources have been major features in the history of the Po Valley over the centuries, making it one of the agricultural heartlands of southern Europe, since the soil has been continuously accumulated by the presence of the Po and its more than one hundred tributaries (Brandolini and Carrer 2020).
However, the dynamics and development of hinterlands during the Iron Age have been scarcely addressed and understood in northern Italy, as excavation projects and regional studies have been primarily focused on major sites, with few comparative analyses and overviews. Town-hinterland relations, and the complex strategies beyond food supply and the extraction of other subsistence goods, e.g., timber, should be a focus of further research, as well as the social impact of towns on rural communities (Cowley et al. 2019;Falconer 1994;McMahon 2020;Smith 2014).
The available data indicate that the emergence of an early nucleation process in northern Italy strongly impacted the organization of the countryside, at least since the Bronze Age but more visible after the opening of new trade paths during the second half of the sixth century BC (Quirino 2017) . Archaeological investigations have revealed early evidence of rural land reclamation and water management (Ortalli 2010), and the establishment of several clusters of farmsteads, hamlets, or villages, with small cemeteries nearby (Zamboni 2018b). More in detail, on the Emilia Plain several examples of late sixth and fifth century BC small and medium rural sites are known, interpreted either as isolated farmsteads or small villages, including Baggiovara (Losi 2011;Malnati 1988;Stoppani and Zamboni 2009), San Claudio (Malnati and Losi 1990), Magreta (Cattani 1994), and Fiorano Modenese (Locatelli 2006). The inland territory of Adria has also been investigated through excavations at the rural site of San Cassiano di Crespino (Harari and Paltineri 2010). The site of Forte Urbano, near Castelfranco Emilia (Buoite 2017;Malnati and Neri 2008), illustrates a different type of structured small village (c. 1 ha in area) during the fifth century BC. The built environment, with a defensive moat-and-ditch system and a regular internal grid of water canals, recalls some of the features already described for the major centralized sites. The timber-framed houses and other buildings inside these rural sites usually have one or two rooms and thatched roofs supported by one or two rows of posts. The presence of courtyards and small granaries is also suggested, yet without clear evidence of wealth accumulation or social differentiation. Common features are kilns to supply local pottery and other small-scale production facilities (Stoppani and Zamboni 2009).
Given the generally low level of material culture and economic diversity (e.g., the scarcity of imported goods, including fine ware and amphorae), hinterlands in the Po Plain seem to confirm the traditional model of a power imbalance between town and village, with the rural agricultural communities supporting the consumer city (McMahon 2020, with alternatives). Yet our limited knowledge of hinterland areas could easily underestimate the scale of production and their sociopolitical role. The presence of nonagricultural and noncontiguous hinterlands (McMahon 2020) can also be assumed, especially in marginal geographical areas, like the inner swamps of the Po Delta, the alluvial lowlands, or in other low-density interfaces.

Population Growth and Immigration
A common characteristic of urbanism, in whatever form, is that it is a context of social plurality (Mogren 2016) attractive to a certain number of people who lived in nucleated sites in greater density (than in rural communities), thanks to the perception or promise of economic improvement and a better quality of life with more social connections. Paradoxically, there is also a higher mortality rate due to poverty, violence, and disease (Algaze 2018;Scott 2017).
In northern Italy several large or high-density agglomerations show early and extremely rapid demographic growth and nucleation, as confirmed by thousands of graves per site, that can hardly be explained by natural population increase alone (see Feinman 2018, 21). Apart from massive colonization movements that may have sometimes occurred (Fernández-Götz 2019), it is likely that the majority of people were of local origin or immigrated from neighboring regions, because centralized settlements "absorbed immigrants and resources from a wide hinterland, and their diverse inhabitants engaged in mass production and longdistance trade" (McMahon 2020, p. 292).
With regard to the Bronze Age, an average of 125 inhabitants per village has been estimated for the Terramare society, with an overall estimated population of 150,000 individuals in the earlier periods (c. 1650-1450 BC) (Cardarelli 2018). The substantial population increase is explained both by internal growth and the progressive penetration of small groups coming from adjacent and more distant areas, reaching around 1000 people living on the larger sites, up to 20 ha, in the later periods (14th and 13th centuries BC) (Cardarelli 2018). It has also been argued that the Terramare collapse was followed by a huge movement of people (Bettelli et al. 2018;Cardarelli 2009Cardarelli , 2018Kristiansen 2018;Vanzetti 2013), and consequently the alluvial plain south of the Po River remained deserted for centuries. Regarding human mobility and interaction, strontium and oxygen isotope analyses from the cemeteries of Frattesina and other Bronze Age sites in the Polesine area and the Emilia region (Cavazzuti et al. 2019), suggest movements of people within a territorial radius of 50 km. This result confirms the scenario of an internal process of stabilization for the cultures of the Late Bronze Age in northeastern Italy, with people coming to the new trading hub of Frattesina mainly from local or neighboring geographical areas.
A similar reconstruction for the Iron Age is hampered by a lack of studies addressing population provenance and estimation. Conversely, population increase during the nucleation and centralization process has traditionally been explained in Italian Etruscology by means of the highly problematic "colonization" model (Della Fina 2008). This approach suffers from a text-based and "culture history" bias, entangled with an uncritical emphasis on ethnicity and ethnic identity, perceived as long-lasting and immutable cultural traits present in the archaeological record, regardless of the ongoing debate on mobility and interaction within postcolonial studies and theoretical archaeology (Bradley et al. 2006;Dietler 2010;Donnellan et al. 2016;Driessen 2018;Van Dommelen 2006. This culture-historical ethnic narrative is (as usual) based on supposed "invasions" and expansions: this involves the undisputed dominion of the Etruscans, who came from the mainland south of the Apennines and built an imagined (sensu Anderson 1991) Etruscan "empire" led by an aristocratic society (see also criticism in Smith 2017, pp. 178-179). This approach fails, however, to explain the complexity and fluidity of the archaeological evidence, and an overall rejection of this culture-historical paradigm is still much needed within Italian archaeology (Zamboni in press b).
On the other hand, the rapid growth of many centralized sites in the Po Valley, even in cases of low-density population, cannot be entirely explained by internal processes, and it must be presumed that immigration played a significant role (Cardarelli 2018), although within a limited territorial range. Unfortunately, as no isotope results are currently available for this period, our understanding is limited to generic considerations based on population/depopulation patterns. For Bologna, for example, a massive movement from neighboring large villages that were depopulated during the first half of the eighth century BC has been suggested (Ortalli 2018;Vanzini 2018). In turn, however, these early Iron Age villages (namely Fiera, San Donato, and Savena-the few excavation trenches in the Fiera area alone yielded more than 1300 graves) must have been populated in their earliest phases by people coming from other regions, probably the Polesine or the Apennine areas, because the Emilia Plain had remained completely deserted after the Terramare collapse around 1150 BC (Cardarelli 2018).
An analogous flow of people could also have occurred in Veneto, from the sites previously occupied during the Final Bronze Age, such as Frattesina, Villamarzana, Montagnana, and their hinterland, to the new large-scale settlements of Este, Padua, and Oppeano (among others). The evidence for immigration to Verucchio is less clear, but it may have been linked to the abandonment of the surrounding hilltop sites at the beginning of the first millennium BC (Rondini and Zamboni 2020a).
For the new foundation of the sixth century BC emporia, such as Spina or Forcello, we can presume the arrival of newcomers arriving from different regions, mainly the Po Valley but also from other Adriatic and central Italian regions. In Spina there may also have been a minority of immigrants bearing Greek lifestyle and culture. This flow points to a multicultural environment that is also suggested by the heterogeneity of languages and dialects used in Spina for hundreds of nominal inscriptions (D'Ercole 2018; Zamboni 2016).

Social Authority and Stratification
Every form of aggregated site, including centralized and hierarchical types, reflects the social context in which the site emerged (Moore 2017). The traditional checklist approach sees the city as the trigger of increasingly complex sociopolitical mechanisms. In contrast, when the division of labor and the development of specialized craftwork and local production are considered, as has been done in more recent studies, then the appearance of complex settlements is rather perceived as the outcome of social transformations, to the development of which, nevertheless, urbanism, in turn, contributed (Moore 2017).
In northern Italy, though, previous archaeological research has placed excessive emphasis on elites and high social ranks, as well as the exchange of prestige goods. Consequently, the traditional and still prevailing approach tends to overemphasize the role of a powerful "aristocratic" ruling class, perceived mainly in the wealth and luxury of funerary assemblages. The elites, mainly considered in a social-evolutionist fashion, would thus have promoted and led the Final Bronze and Early Iron Age centralization process south of the Alps, exercising firm control over other economic and social activities (e.g., Fernández-Götz 2018; Malnati 2004Malnati , 2011. A different scenario has been outlined only for earlier periods: the Terramare society of the Middle and Recent Bronze Age has been sometimes interpreted as more egalitarian, with a transmission of power mainly based on kinship. The sparse and homogeneous settlement pattern-hundreds of small structured villages surrounded by ditches and embankments-is incompatible with pronounced forms of hierarchization. Even the early adoption of the funerary practice of cremation, with the ashes placed inside a coarse-ware urn together with ornaments and other grave goods (Cardarelli 2014), concerned a large part of the population, without marked signs of social differentiation. Moreover, a comparative approach indicates that an economy based on internal agricultural resources, involved in intensive exploitation and massive landscape modifications, like in the Bronze Age Po Valley, could easily develop collective forms of cooperation (Feinman 2017;Jennings and Earle 2016). This scenario is not in contrast with the suggested presence of certain settlements highly specialized in the mass production of goods, especially textiles (Cardarelli 2018;Sabatini et al. 2018).
During the last stage of the Bronze Age, the formation of larger polities of villages, able to manage larger-scale infrastructures and land engineering, has been supposed (Cardarelli 2018;Cupitò et al. 2015). Yet the social structure likely remained kinship based, since the presence of some distinctive grave goods, such as a few bronze weapons in male burials, and metal hoards (Cardarelli 2018), does not seem sufficient to identify an ongoing process of hierarchization of society and the formation of elite groups (for a parallel, see Kienlin and Stöllner 2009). However, there is wide agreement on the passage from more inclusive Bronze Age communities based on kinship to highly hierarchical societies dominated by high-rank elites in the Early Iron Age (Cardarelli 2018).
A closer look at Verucchio, though based mainly on funerary data, seems to confirm this picture. While the scarce ninth century BC grave assemblages display few signs of social or gender differentiation, during the eighth century BC the hierarchization process of Verucchio society grew rapidly, as reflected by funerary ritual (von Eles and Baldelli 2017). A minority of tomb structures became more complex, with a deep chamber cut into the bedrock, sometimes containing multiple depositions, with timber planks separating upper and lower levels, and an undecorated gravestone as a marker. Moreover, the concentration of numerous weapons, metal horseharness and chariot components, wooden furniture, banqueting vessels, and jewelry gives a vivid image of a highly self-conscious elite class that displayed their power and wealth through the exhibition of kin bonds and aristocratic ideals during the funeral (Negrini 2018). The Verucchio elite was perhaps ruled by few high-ranking individuals-such as the so-called "prince" of the famous grave Lippi 89, buried with a wooden throne and symbols of power-belonging to restricted family groups, faithfully attached to their traditions and ceremonies, with an emphasis on warfare and competition.
On the other hand, this "aristocratic" model is not as self-explanatory as it seems at first glance and cannot be uncritically applied to other sites and contexts. In fact, the high-rank elite model is based on a disproportionate attention to funerary matters and an exaggerated (almost obsessive) focus on opulent graves and symbols of power (Schumann and van der Vaart-Verschoof 2017; see criticisms in Kienlin and Zimmermann 2012). In the traditional approach "emphasis was situated too heavily on the strategies of elites" (Feinman 2018, p. 18).
A different perspective based on comparative analogies and social studies indicates that marked differences in wealth, especially if limited to the realm of funerary rites, are not automatically correlated with a higher degree of political complexity (Feinman 2017). The agency behind societal change, including the development of complex and structured economies and nucleated settlements, "has never been limited to the realm of the elite" (Feinman 2018, p. 16).
On the contrary, for centuries in the protohistoric era, wealth in the Po Valley was based on internal agrarian resources, a precondition that could promote collective forms of governance. It is also possible-even though this may be perceived as counterintuitive to our Western preconceptions-that increasing settlement numbers are due to "reverse dominance hierarchy" mechanisms, namely reactions of egalitarian groups preventing the emergence of potential leaders, limiting domination (Jennings and Earle 2016).
If, though, a society depends more on external resources (e.g., Verucchio, situated on the margin of the fertile plain, on a hilltop dominating Apennine pathways), more vertical, despotic, and autocratic forms of power are to be expected (Blanton and Fargher 2011;Feinman 2017Feinman , 2018. This is because its economy will be tied to external networks, built and managed by the elites, and exotic goods (metals or other material of "intrinsic" value, like amber for Verucchio) that are key elements of exchange and high-status maintenance.
Therefore, if we look at evidence other than grave goods, we see that in the Po Valley during the Final Bronze and Early Iron Ages there is no clear evidence of elaborate "private" architecture, such as monumental residences or palaces, or monumental tumuli, which are elsewhere indicators of family wealth concentration and despotic central authority (Feinman 2017; on tumuli see Naso 2011). Conversely, we have described how during the settlement nucleation process in northern Italy there was rather widespread resource investment in community features and constructions, including enclosures, water management, gridded streets, and (although rarely) public areas, that could "potentially enhance the well-being or standard of living of subalterns as well as elite" (Feinman 2017, p. 466).

Commoners, Artisans, and Merchants
Although the role of the upper classes as agents of social change is not to be underestimated, especially during the Early Iron Age and Orientalizing period (Burgio et al. 2010;Malnati and Gamba 2003;von Eles 2013), a more nuanced picture could be outlined regarding different forms of cooperative social entities (Ortalli 2013). It is worth remembering that most of the population aggregated in the new centralized settlements would always have been composed of commoners and workers: "those who came together to form the first cities were largely farmers, herders, and fisher folk" (Jennings and Earle 2016, p. 475). And when more heterarchical, rural societies move to more centralized social forms and agglomerations, they usually retain "rural" settlement forms and social units, which are the basic households (Jennings and Earle 2016;Moore 2017).
Moreover, the social interaction patterns between artisans and their clients, whether elites or commoners, have not been adequately addressed until recently, as well as the role of materiality and manufacture in shaping social relations (Brysbaert and Gorgues 2017; see also Ingold 2013). Although some Bronze and Iron Age working tools have been classified (Iaia 2014), the role of craftwork and craftspeople in the formation of aggregated and nucleated settlements has been regularly overshadowed by the (supposed) preeminence of aristocrats.
For a reassessment of merchants and middle-class groups, especially during the trade explosion of the sixth and fifth centuries BC, Spina is once again informative. The site was mainly a commercial center, ruled by a wealthy merchant class, whose inhabitants came from various places of origin and lived there in a multicultural environment. The settlement layout and the grave assemblages both point to an equalitarian redistribution of wealth, with a substantial absence of high rank or outstanding features-such as palaces, buildings of larger size or higher artistic level, or monumental tombs-and more emphasis on portable wealth (jewelry, metal furniture, and imported figured pottery), rather than on monumental constructions.
The bourgeois and cooperative character of Spina's society is confirmed by the absence of family names, as documented by hundreds of graffiti on potsherds, which bear only single names of Etruscan, Greek, or other origin (Zamboni 2016; see also Scott 1998, for the coercive state's imposition of family names). Moreover, if we accept the provocative thesis of Vickers (2017), that within the classical economy pottery was more like a by-product, a surplus that served as a space-filler in large ship cargoes, "distinguished-looking, but comparatively cheap ceramic surrogates of the Attic silver vessels with which real trade was conducted" (Vickers 2017, p. 123), then the abundance of Greek-figured vases among the grave goods at Spina should not be seen as a sign of hierarchy and high-rank wealth but instead of widespread, horizontally distributed well-being within an entrepreneurial society.

Nonelites and Marginality
Another context for outlining the presence of multicultural nonelites and their relationship with the hinterland areas is the alluvial plain west of Bologna. There, sixth century BC funerary evidence reveals the presence of a rural community settled in a boundary region between the Golasecca culture to the northwest, the Veneto region to the northeast, and the Etruscan towns to the east, without any sign of settlement nucleation (Zamboni 2018b). In the small bi-ritual cemeteries in this area, typical grave goods assemblages, mainly of female type, show several influences coming from the surrounding northern and Alpine cultures (including specific types of bronze pendants, fibulae and ornaments, bronze belt-plates, and toiletry items). On the other hand, there is no visible evidence of power or warfare, whether prestige goods, luxury items, or weapons. Funerary practices in sixth century BC western Emilia were abnormal also because pottery is completely missing from the grave goods assemblages, suggesting the exclusion-perhaps prohibition-of the social performance of drinking from afterlife beliefs. Overall, the nonurbanized and divergent community of the western Emilian Po Plain looks like a nonelite society established in a frontier region during a formative stage with a lack of hierarchy markers and a low level of social differentiation (Zamboni 2018b).
A final aspect of subaltern groups has long been ignored by archaeological research in northern Italy. A recent reappraisal has, however, highlighted the presence of less visible social groups, such as slaves and other marginalized persons (Saracino et al. 2017). At sites in the region, the contextual association of unusual traits, such as burial displacement, signs of disease, malnutrition, or violence, and markers of heavy work, supports the scenario of pronounced social inequality, especially in Iron Age Veneto and, to a lesser extent, in Bologna and the Alpine regions (Perego et al. 2015). A direct connection between the centralized form of settlements and evidence of social inequality, poverty, and disease, as outlined for other regions and periods (Algaze 2018), could be a matter of further analysis.

Conclusion
In writing this paper I highlighted to what extent ongoing archaeological projects and theoretical advances could undermine the primitivist perception of an underdeveloped protohistoric Europe (Collis 2016), prone to the idealistic prejudice that cultural innovations could have flourished only after contacts with supposedly "advanced" civilizations (as far as the Italian Peninsula is concerned, the Greek arrival in Campania during the eighth century BC, or the supposed Etruscan conquest of northern Italy). The regions between the Alps and Apennines are deeply involved in this paradigm shift (Pearce 1998), since no external colonization or civilization is needed to explain the early and endogenous population growth and development of society and settlement patterns there (Cardarelli 2018).
Northern Italy must also have played an intermediary role in the broadest scenario of south-central Europe, because the region shows a remarkable precocity in settlement agglomeration and site nucleation. The process started not later than the mid-second millennium BC with the Terramare in the middle Po Valley, with trajectories of both discontinuity and continuity seen in Late Bronze Age polities. It is assumed that these local Bronze Age cultures, already involved in international trade and with wide-ranging connections, provided a crucial background for later population developments. In fact, during the first millennium BC, if compared to the picture outlined for northern Alpine regions (Buchsenschutz 2015;Fernández-Götz 2018;Stoddart 2017), a centralization process appeared earlier in northern Italy, at least in the ninth and eighth centuries BC (as seen at Este, Padova, Oppeano, Bologna, Verucchio, Castelletto Ticino), in close parallel with the regions south of the Apennines, i.e., Etruria and Latium (Guidi 2008(Guidi , 2010Pacciarelli 2016).
This early development could be explained by a set of preexisting models, traditions, and technical skills, including timber architecture and water management, that could have pushed and facilitated the planning and shaping of complex agglomerated sites south of the Alps. This model does not exclude, of course, cultural interaction and close contacts with central Italy and the Mediterranean, especially after the seventh and sixth centuries BC, but it avoids preconceptions about one-way dependency relations.
On the other hand, while some of the centralized centers in northern Italy survived and flourished, other sites declined or even disappeared between the seventh and sixth centuries BC, offering examples of not only eventful, éphémère, or fragile urbanism, as outlined for the regions north of the Alps (Arnold 2010;Brun and Chaume 2013;Fernández-Götz and Ralston 2017;Stoddart 2017), but also of successful long-term habitation. A new wave of settlement nucleation took place in northern Italy after the mid-sixth century BC, when newly founded sites of medium or small dimensions (between 6 and 20 ha), including the emporia of Adria, Spina, and Forcello, held key roles in the exchange networks between the Mediterranean and central Europe (Fig. 5).
At the same time, while I have reassessed the role of the Po Valley in the wider context of the European debate on settlement centralization and societal complexity, I also explored alternatives to "common-sense" and classical forms of urbanism and social formation. Different types of agglomerated sites with divergent developmental trajectories have thus been presented, from densely and sparsely populated polities to extensive nucleated settlements, perhaps with forms of low-density occupation, and high-density trading hubs, characterized by a combination of recurrent distinctive attributes, including trading networks, connectivity, an engineered environment, population growth, and social stratification.
Several questions about these early structured aggregations in the Po Valley remain, however, especially regarding social structures. First, even if we assume a timely disentanglement of the simplistic equation between urbanism and social hierarchy, it remains unclear if the major outcomes of the settlement centralization south of the Alps were encouraged and controlled by high-rank elites and central authorities, as assumed in previous models (Smith 2016, p. 165), or if there is space for more cooperative, bottom-up mechanisms. In this regard, while egalitarian and isonomic forms of power have been suggested for the Bronze Age Terramare and the early town of Bologna, the varied archaeological picture of the Po Valley allows us to reassess the role of intermediate social ranks, including lower-ranking elites, productive classes, merchants and artisans, and other categories of commoners. The abundance of public provisions, such as water supply, gridded streets, and fortifications, along with the availability of local resources, suggests, from a comparative perspective, less autocratic rule and more collective forms of power (Blanton and Fargher 2011;Feinman 2017). On the other hand, the study of marginalized people, however poorly visible in the material record, is a primary indicator of increasing social inequality within the centralized societies.
Second, our limited evidence cannot indicate whether the centralized sites of the Po Valley represent "powerscapes," namely places where ideological and shared mnemonic practices played a key role in shaping the invention of the urban tradition and mythological discourses, perhaps with material objects being actively involved in the process. In specific places that acted as foci for large group meetings in times of ceremony, crisis, or decision making, a sense of theatricality could be also envisaged, namely the choreographed movement of people during processions or other public activities (Moore 2017).
The latter aspect, which likely involves the concept of seasonality, allows us to address the idea of temporality and cycles of durability. I have suggested for some sites the presence of low-density areas, inside or outside the main town perimeter, that could have been used for short-term or occasional craft activities, including periodic markets, when these spaces might have been occupied by hundreds or thousands of temporary dwellings and other mobile structures. An insight into the biographies of buildings could also deepen our knowledge of periodic cycles of management and rebuilding, particularly frequent in the unstable environment of an alluvial plain, beyond the rhetorical discourse of urban stability and permanence.
In sum, the Late Bronze and Iron Age population and settlement patterns in the Po Valley offer a palimpsest of variability and diversity that require-in addition to more extensive excavations and landscape projects, and more detailed analyses of the agency of single structures and objects-better conceptual tools to overcome unreliable notions of linear progress and presumed uniformity.