At first glance, because the engaging fascination of history overshadows the actual reference to geometry, the focus of The Italian Piazza Transformed does not immediately seem to be the relationships between mathematics and architecture. I must therefore apologize to the author for the delay in suggesting her work for the book review section of the Nexus Network Journal, when the editor asked for my collaboration. The book was still lying on my desk, among those waiting for a second careful reading, when I realized that it indeed deserved a presentation to our readership, because of its subtle approach to the study of the form while inquiring into the design of public spaces as a proper and innovative feature of Italian cities in the Communal Age, that is, the era of the independent comune, city-states, from the twelfth to the fifteenth century (Fig. 1).

Fig. 1
figure 1

Book cover, The Italian Piazza Transformed

The book deals with the two main squares in Parma, that of the Cathedral (duomo) complex and that of the City Hall (municipio), and asserts that their regular shapes act as the first statements of a new urban concept of the communal age, in which geometry is used as a claim for power, imposing order on the irregular fabric of the medieval city.

The European city exists because of the public space, and the book focuses precisely on the importance of the public space in the formation of the modern city, which emerged in the Middle Ages when the comuni declared a political role for themselves and autonomy for secular cities in the quarrel between the two most powerful institutions, the Church and the Holy Roman Empire.

Areli Marina is Assistant Professor of Architectural History, Art History, and Medieval Studies at the University of Illinois, Urbana-Champaign. Because she knows Italy’s cities and language well, she is able to access directly original ancient literature and archival documents, even those of the twelfth and thirteenth centuries, when a new urban culture was reviving the splendor of Rome and reinventing public space. She is able to grasp the great importance that “voids” have in the life of Italian cities and her thesis focuses on the space in between buildings, rather than on the architecture itself.

The original character of this particular approach to the city lies in the reading of the piazza as a network of voids that defines the urban character, rather than reading it as a mere cluster of buildings. In her introduction she stresses the differences between her approach and that of earlier studies, explaining the reasons for the absolute significance of the examples she studied.

According to Marina, Parma is the first city in Italy where the local rulers applied a new urban design strategy to assert their power, anticipating the Tuscan cities by a century, and acting as a model for the market towns of the thirteenth and fourteenth centuries.

This explains why the research, which deals with a single provincial town, will surely become an fundamental reference for the knowledge of the Italian city and its transformation after the collapse of the Roman Empire, when the pressure of the peculiar dichotomy of power existing in Italy in the Middle Ages would define and influence urban life, echoing in local culture until quite recently. In fact, the tug of war between the two modern folk characters created by Giovannino Guareschi,Footnote 1 Don Camillo and Peppone, illustrates the endemic stress between secular and religious power that shaped the city and continued to animate the people during the age of the Cold War.

Marina introduces the book by quoting the Etymologies by Isidore of Seville, beginning with the statement that the word city means both the buildings (urbs) and the citizens’ social network (civitas). This dichotomy encapsulates the medieval understanding of the city, and Marina demonstrates how the two squares in Parma are the panoptical declaration of urban identity. She bases her thesis on the interwoven testimonies of documents and monuments, identifying pieces of evidence in the surviving architecture and in the survey of urban sites.

The introduction explains that the research involved searching through four bodies of material to answer the many questions about the nature of the two large squares and the reasons for their shapes:

  • the physical evidence of the sites;

  • contemporary literature about Parma history and architecture;

  • historical representations of the city;

  • secondary literature about local and northern Italy political and visual culture.

The study of these materials enabled Marina to reconstruct the conditions of the piazza’s foundations and to see the design concept with “period eyes”.

The first step in the analysis regarded the urban space, reconstructing the historical events and facts of the building, shaping the original perimeter and further transformations, with special attention to the relationships between buildings and site. The second step was the reconstruction of the city of Parma (the urbs) in the Middle Ages. The third step was identifying the patrons, the historical events and the successive military and political leaders. Finally, the last step was a consideration of the cultural environment and the education of the city elite.

The final topic is the struggle for authority in the Communal Age, when the city (the civitas) declared its independence from the two leaders fighting for power, namely the Pope and the Emperor.

The book is divided in two parts, each of which is subdivided in two chapters. Part I, “The production of Order”, is the pleasant story of the construction and description of the two squares. Piazza del Duomo grew first, starting with the building of the Baptistery, which shaped the urban space between the Bishop’s Palace and the Cathedral. The first chapter explains how the particular site and the shape of the octagonal Baptistery demonstrate the existence of a clear “political” design behind the aim to impose a geometrical pattern on the square. Later, the increasing strength of the citizens’ secular authority lead to the creation of the Piazza del Comune: a new, larger square which was arranged on the site of the earlier Roman forum. The second chapter addresses the foundation and the growth of this secular compound, whose design pursued the concept of order in the global perception of urban space, by the imposition of a quality standard on the square and on citizens’ behaviour.

Part II, “The Piazza and Public Life”, investigates the Legislation of Order that made the building of the Piazza del Comune possible. Piazza del Comune was intended to testify to the secular city’s social order in the urban decorum, granted by laws and city officers. The enactment of Statuti, statutes, underlined and extended what was symbolised in the abstract by the space’s geometrical form. The last chapter closes by stressing the importance and significance of the Roman heritage in the culture of the Middle Ages, finding evidence in the splendour of the architecture and in the expression of civic spirit through civic space.

Three appendices, many notes and an extended bibliography offer an overview of the full apparatus of documents that support the whole research and—most noticeable—underline the importance of the study of the mathematical elements, such as measurements and shapes in the comprehension of historical architecture, discussing the difficulties of such a task (Fig. 2).

Fig. 2
figure 2

Extracts from Areli Marina’s figs. 33, 34, 47 and 98, schemes that show the use of proportional systems based on the doubling of a square module in the elevation of the Baptistery of Parma, and how the same criterion relates the squares that define the plans of the two squares

The first appendix, “On Measurement, Module and Geometry in Medieval Parma”, is a synthesis explaining why there is a lack of scientific evidence necessary to state a final interpretation of the metric “measure” in terms of numbers. For this reviewer, this Appendix was fundamental for understanding why Marina, who is so precise in her analysis, describes (geo)metric relations in reference to approximate measurements expressed in metres, and limits herself to looking for individual geometric relationships without seeking an overarching solution that would be confirmed by round measurements.

In the case of the Duomo, the unit of measurement of reference is the Roman foot, which in Parma is the dimension of the bricks used in the square. Since as part of my own research I personally had carried out a survey, I am quite familiar with the measurements, and I was surprised by the author’s use of this approximation, in part because when my team and I had undertaken our survey, one of our goals was to find the modular matrix of the square. Reading the Appendix, which ably summarises the history of local units of measure, which in Italy, as we know, vary according to period and location, I understood the reason behind Marina’s decision.

In essence, she renounced a metric reading because there is no way to be certain of the unit of measure used in the Middle Ages, since the Roman foot does not appear to have any relation to the foot used in the Renaissance, and cannot in any case be considered “stable”.

With elegance, Areli Marina adds an important piece to the puzzle, confirming the importance of a careful survey of the urban space and her consideration of the architectural survey as a matter of knowledge more than a technical procedure for measurement.

The Italian Piazza Transformed is a book, which is indeed worth reading. It was awarded the 2013 Howard R. Marraro prize for the best work in Italian Catholic history from the American Catholic Historical Association.