It appears that since the early eighth century and well into the twelfth, there was a steady supply of whetstones from Mostadmarka to markets and urban sites in southern Scandinavia. The precise volume is hard to determine, but a rough estimate suggests that in Ribe an annual average of approx. 170–200 fragments of Mostadmarka and Eidsborg whetstones were deposited.Footnote 11 In some cases, multiple fragments may have come from the same whetstone; however, many of those who acquired whetstones in Ribe, particularly during the site’s seasonal-marketplace phase, will have used them elsewhere and discarded the remains there. Hence, as an absolute minimum, an average annual supply to Ribe of several hundred Mostadmarka and Eidsborg whetstones—until c. 820 nearly all of them from Mostadmarka—seems likely, sufficient to cover more than half of the demand among craftsmen, traders, and other buyers there.
The likely shipping site for the Mostadmarka whetstones is Lade, 20–25 km north-west of the two Mostadmarka quarries (Figs. 1 and 3). From the late ninth to the early eleventh centuries the prominent manor Lade (Old Norse Hlaðir, ‘storing place’ or ‘loading place’) was the residence of five generations of Lade Earls, high-level political agents in Scandinavia. The first of these, who apparently already resided at Lade (Schreiner 1928:9–10), became King Harald Fairhair’s earl, while the last ruled Norway as the earl of the Danish kings Harald Bluetooth and Sven Forkbeard. The manor is situated in the second richest agricultural region on the western coast (after Jæren in Rogaland, Fig. 2), on a small promontory with several natural harbours on the southern shore near the mouth of the Trondheim Fjord.
According to the skaldic poem Háleygjatal (‘Enumeration of the Háleygir’, composed c. 985), the Lade Earls originated in Hålogaland, which comprises the approx. 650 km of coastland from northern Trøndelag to the Malangen/Lyngen area (Fig. 2). Further north and east lay Finnmark, the land of the Finnas (Sámi). From these northern regions came highly desirable goods that the Háleygir obtained from the Finnas. Describing his commodities during his visit to King Alfred’s court c. 890, Ohthere from Hålogaland listed walrus tusk (ivory), rope from walrus and seal hide, down and feathers, and fur from marten, bear, otter, and reindeer (Bately 2007:46).
This trade had a long history prior to Ohthere’s time. Jordanes, in his mid-sixth-century History of the Goths (ch. 19, Mierow 1915:56), writes of the Adogit (alogii) people in Scandinavia, who live where summer has 40 days without nights and the winter 40 days without sun. The description fits Hålogaland, and the Adogit are commonly identified as Háleygir (Sitzmann and Grünzweig 2008:21–22; Svennung 1967:32–41). Jordanes also mentions the neighbouring Scrithifinni, apparently the Finnas, which he identifies as hunters and gatherers. From these northern regions come exquisite furs enjoyed by the Romans, Jordanes reports (ch. 21, Mierow 1915:56).
Evidence collected in Hålogaland demonstrates increasingly larger and more seaworthy ships and a rise in seafaring from the seventh century onwards (Storli 2006:22), in tandem with an aristocratic stratum with access to long-distance goods. A number of prominent manors have been identified along the coast (Fig. 8; Berglund 1995; Hansen and Olsen 2004; Holberg 2015), but only one of these, in Borg, Lofoten, has been thoroughly excavated: In the remains of the hall section of a 67-meter longhouse, rebuilt to 83 meters, shards from 15–16 glass vessels were found as well as 36 glass beads, rather evenly spread out over the longhouse’s existence (seventh to tenth centuries). Six vessels can be provenanced respectively as Anglo-Saxon (one from the seventh century, two from the eighth), Rhinish (one, eighth century), and Continental (two, ninth to tenth centuries). The beads are less securely provenanced; they were probably imported to Scandinavia and are common occurrences in southern Scandinavia and the Baltic (Holand 2003; Näsman 2003).
Although the Borg finds demonstrate that glass vessels were available to seventh to tenth century west-Scandinavian aristocrats, the latter, unlike their peers in southern and south-eastern Scandinavia, did not include them in grave furnishings (Holand 2001:164–165). Fortunate depositional and post-depositional circumstances and the sieving strategy applied in the particularly find-rich north-western corner of the hall section appear to be the main reason for the uniqueness of the artefact assemblage in Borg.Footnote 12 However, the frequent occurrence of glass beads and copper-alloy brooches in graves in Hålogaland (Eldorhagen 2001; Vinsrygg 1979 tables II–IV) and elsewhere in western Scandinavia (Røstad 2016:52–92, 273–97) corroborates the eighth-century phenomenon evidenced by the Ribe whetstones: Regular long-distance trade from the Arctic to the southern North Sea zone was indeed undertaken from aristocratic manors, including other than Borg, in the seventh–eighth centuries.
In written evidence, the trade in commodities acquired from the Finnas through tax, tribute, trade, and plunder is a recurring theme in royal politics from the time of the first king of Norway, Harald Fairhair (reign c. 872–932), until the twelfth century. Harald secured the transport of these and other commodities along the coastal sailing route, the Norðvegr (Fig. 2), by naming local chieftains earls of the main regions along the route; its southern end in Hordaland and Rogaland was his own heartland (Skre 2018b). In Møre he appointed Rognvald and in Trøndelag/Hålogaland appointed Håkon, the first Lade Earl (Fig. 2).
Prior to that, a prime driver behind political integration processes along the route seems to have been the securing of seaward traffic in general, but in particular probably the transport of Arctic commodities to sites and markets along the west-Scandinavian coast and in the southern North Sea zone. Integration of Hålogaland and Trøndelag appears to have developed well before Harald’s time (Bratrein and Niemi 1994; Holberg 2015; Koht 1919:16; Schreiner 1928:9–10). Lade, positioned at the southern end of this long stretch of land, is a likely place where a variety of Arctic commodities from Finnmark, Hålogaland, and Trøndelag were stored—the latter region would contribute whetstones and possibly iron (Stenvik 1997) and furs (Holm 2015; Lindholm and Ljungkvist 2016) from the neighbouring woodlands—to be loaded onto ships headed for southern markets. The common occurrence since the late-sixth century in several east-Scandinavian regions of gaming pieces made from North-Atlantic whalebone (Hennius et al. 2018) suggests that the Hålogaland/Trøndelag trade network also extended overland eastward to the Baltic.
The steady supply of Mostadmarka whetstones to southern Scandinavia through the eighth to eleventh centuries and the quarry’s proximity to Lade suggests that these stones were a common commodity in the ship-bulk of long-distance traders from Trøndelag and Hålogaland. All the commodities mentioned by Ohthere were high-value items for a narrow group of buyers: either luxuries (down, ivory, fur) or sought-after utilities (ship-ropes from hide). These high-quality products from Arctic Scandinavia were in high demand in the aristocratic segment in the Continent and the British Isles. At the same time, Ohthere’s list should not be taken as exhaustive; the commodities recorded would have been of interest to his audience of royal scribes and officials, whereas commodities for craftsmen and the general population, such as reindeer antler (Ashby et al. 2015), oil from marine mammal blubber (Nilsen 2016), gaming pieces from whale bone (Hennius et al. 2018), and whetstones, might not have been deemed worthy of mentioning in the royal quarters.
All materials in Ohthere’s list are perishable and are only preserved in exceptional cases.Footnote 13 The identification of the Mostadmarka origin of a substantial portion of whetstones in sites such as Ribe, Hedeby, Kaupang, and Oslo adds a non-perishable commodity to the list. Their continuous occurrence in high volumes at these sites allows their cautious use as a proxy for the trade in commodities from the Arctic transported on the Norðvegr along the western coast of the Scandinavian Peninsula in the seventh to tenth centuries.
Taking Up Raiding in The West (c. 789–850)
Essential constraints and opportunities of Viking-ship commanders of the 780s–850s are discussed in the following, suggesting how they may have influenced their decisions on where to raid in various periods. The discussion is framed by the substantial trade in Arctic commodities along the west-Scandinavian coast evidenced by the Ribe whetstones. The interests of various groups in this trade produced both conflicts and coalitions.
The most prominent concern of Viking-ship commanders is the coalition between one of their primary targets, long-distance traders on the Norðvegr, and kings along the route. While this coalition appears to have had existed since the Roman Period, strengthening of royal authority in the late eighth century posed an obstacle for Viking-ship commanders, who now faced a stronger adversary.
Their second concern, emerging through the 820s–30s, was that they were victim to their own success: the profitability of overseas raiding attracted increasingly greater numbers of ships and men to that enterprise, with the resulting competition reducing their spoils. However, this situation also produced a new opportunity: raiders could join forces in Viking fleets that had the necessary strength to conduct successful raids on prosperous and well-defended sites. By overwintering overseas, Vikings could reduce the danger of retaliation from kings and traders based in the homelands for raiding lands and waters where the latter wanted to maintain peace.
Thus, we suggest that Viking raiding overseas began as Vikings became the weaker party in a longstanding conflict in the homelands. That such ‘push’ factors were the key trigger is supported by the character of the earliest raiding. During the first 15–20 years of overseas raiding Vikings struck at widely dispersed sites (see below), suggesting that they were not ‘pulled’ to certain lands so much as they were ‘pushed’ into searching for prey in new waters. As their activities gained volume and momentum through the 820s–30s, the homeland conflict with traders and kings maintained significant influence on where Vikings raided. However, ‘pull’ factors (e.g. the weakening of the Frankish Emperor’s power in the 830s) attained more significance as Vikings overseas gained numbers and strength.
Traders, Kings, and Vikings (Seventh–Ninth Centuries)
Regarding his northward voyage to the Beormas, Ohthere reports that he did not enter their land for unfriðe, often translated as ‘because of hostility’ (e.g. Bately 2007:45, 56–7). However, Christine Fell (1982–3) convincingly argues that the term has a more specific meaning, namely that Ohthere did not have the personal frið status among the Beormas that would have allowed him to travel safely into their land.
There is no mention of such hindrances on Ohthere’s southwards journey along the Norðvegr and into Skagerrak and Kattegat to Hedeby, or indeed across the southern North Sea to King Alfred’s court in Wessex. The latter is a case in point for Fell’s conclusion (1982–3:96) that frið was a personally held privilege and not necessarily affected by hostilities between people from the very same polities or regions. King Alfred’s realm had suffered substantial Viking incursions throughout his lifetime. Apparently, the King still granted frið to this man from Arctic Scandinavia, presumably because he identified himself and was accepted as a trader. Ohthere must have received the same privilege by others to be permitted to travel across the various political and cultural zones on his long route.
Thousands of windblown and mostly barren islands and skerries protected Ohthere’s voyage along the west-Scandinavian coast from the rough winds and waves in the Atlantic Ocean. But intermittently along the Norðvegr occur pockets of relatively fertile land. In the best of these were situated manors rich in monuments and lavishly furnished graves spanning the early Bronze Age to the Viking Age. While rich finds also occur in the much more fertile and densely settled districts in valleys and along fjords further inland, the archaeological record of the outer-coast manors is unsurpassed. Among them, in Rogaland and Hordaland, are the five manors that according to the Icelandic saga tradition belonged to Harald Fairhair. Further north are two additional coastal-manor zones, one in Møre and the other in Hålogaland (Fig. 8). Between the three zones the islands and headlands along the sailing route are too barren to support large or numerous settlements.
Avaldsnes, the most prominent of these coastal manors, is situated at a bottleneck on the sailing route’s southern end (Figs. 1 and 2). Based on excavations here, Skre (2018b) argues that from the third to the eleventh centuries these manors served as supply bases for the sea kings who exerted authority over the sailing route. By fighting Vikings who lurked in the innumerable islands and bays along the route, the sea kings could provide safe sailing for traders and other travellers. Snorri recounts in Harald’s Saga (ch. 22) that every summer Harald and his army searched the islands and outlying skerries, pursued the Vikings that camped there, and drove them over the sea to the west ‒ all the way to the Irish Sea. In the same saga (ch. 24) Snorri writes that Harald outlawed Rolf, the son of his close ally Rognvald, because he had harried in Viken (Fig. 2); the king had strictly forbidden robbery in the realm. Of course, there is ample reason for scepticism about the historicity of Snorri’s accounts, committed to parchment some 300 years after the events. Nevertheless, outlawry is precisely the penalty stipulated in the west-Norwegian Gulaþing law code (ch. 314) for those who renounce the frið and ravage the homelands. Scourging one’s home district was even worse; it was considered an honourless deed and perpetrators were declared níðingr, irredeemable outlaws.
Frið arrangements with kings and earls who controlled various stretches of the Norðvegr, surely involving payment of shares to the latter, would have been vital for long-distance traders as well as for other travellers. Although aristocrats would have had their own ships and men to defend their lives and cargo, it would have lain entirely within their interest to support royal peacekeepers along the route. While the power balance between Vikings on the one hand and traders and kings on the other varied through the centuries, the constellations and roles would have remained relatively constant during the periods when manors along the route show evidence of sea-kings’ presence. At Avaldsnes such evidence (i.e. monuments, remains of halls and other prominent buildings, and extensive food processing) is found from the mid-third to the eleventh centuries (Skre 2018a).
The same person could of course be a trader, Viking, and royal warrior in different waters or at different times—after all, the same skills were needed by all three: seamanship, negotiating abilities, and martial proficiency. While some sea kings mentioned in sagas and skaldic verse were evidently Vikings, Harald appears to have been a warrior who rose to power in a peacekeeping sea-king milieu along the sailing route in Rogaland and Hordaland, subsequently extending his realm from the sea route to the inland (Skre 2018b). Other rulers (e.g. Olav Tryggvason, reign 955‒1000) appear to have spent time in service to kings in other lands and participated in Viking raids before they became kings in their own right.
From the late ninth century, Harald Fairhair and his earls controlled practically the entirety of the Norðvegr sailing route. Already by the late eighth century, kingship appears to have developed at the southern end of the route, in Rogaland and southern Hordaland. Based on new datings from three assembly sites in Rogaland—so-called courtyard sites—Iversen (2018) provides empirical support for Myhre’s (1992) suggestion that in the eighth century trans-regional royal power emerged there. Independently of Iversen and based on other types of evidence, Stylegar and Bonde (2016) date this rise of kingship by the southern end of the Norðvegr to the late eighth century. They maintain that kingship there was modelled after the Anglo-Saxon version, and that the burial rites of the two first Scandinavian ship graves near Avaldsnes—the ships were built c. 770 and 780 and entombed in 779 and the early 790s respectively—were modelled on the Sutton Hoo ship burial in East Anglia (Stylegar and Bonde 2016:10–13).
The increase in the 780s and peak in the 790s in the total number of whetstones deposited in Ribe each year—annual average in ASR 9 of 3.3 and 14.3 (N = 33 and N = 143 respectively, see Table 6) in the two decades respectively—reflects increased activity there. The reason for the increase is probably that this period saw the heyday of trade in the Channel and the southern North Sea zone (Coupland 2002; Verhulst 2002:92). However, the percentage of Mostadmarka whetstones also rises in these two decades to a peak of 75% (ASR 9), probably reflecting a vast increase in trade in Arctic commodities, both in relative and absolute volume. Likely, the main reason for this is the existence of a polity in Rogaland and southern Hordaland that was sufficiently strong to guarantee safe sailing in adjacent waters, and thus, with whom Arctic traders could make frið arrangements. Contemporary developments of royal authority over Viken (Fig. 2) and southern Scandinavia under Sigfred and his son Godfred, kings of the Danes, may be the reason why Frisian and Slavic traders sought the town Kaupang from its very founding c. 800 (Skre 2011a).
The beginning of Viking Raiding Overseas
It appears that the earliest Viking raiders in the west emerged from the western coast of the Scandinavian Peninsula, suggesting a connection to the contemporary peak in the transport of Arctic commodities along the very same coast and the building up of royal authority there. Following a brief summary of the whens and wheres of the early raiding, these suggested connections are explored below.
Beginning in 789, the earliest reported Viking raids in the west were a series of disparate attacks on coastal settlements from the Bay of Biscay in the south to the Atlantic Scottish Isles in the north (Fig. 1). While, surely, many attacks are unreported, the overall chronology in England, Francia, and Ireland is rather well testified. Northern Scotland is the least reported (Barrett 2008), but was probably targeted early. Based on reported raids, beginning in Portland in Dorset in 789, the English Channel coast from Kent and westwards seems to have been hit first (Downham 2017). Thereafter, raids are reported in Lindisfarne in 793 and Monkwearmouth (both in Northumbria) in 794, Ireland and Scotland in 795 (Ó Corráin 1998), Isle of Man in 798, and Aquitaine and the southern Channel coast in 799 and 800 (Walther 2004:168–170).
From c. 806 raiding centred on Scotland and Ireland, and for the following 30 years nearly all raids were conducted there, escalating sharply through the 820s and 30s (Etchingham 1996:Fig. 2).Footnote 14 Ó Corráin (1998:27–28) suggests that from 814–20 (the only period after 806 when chroniclers do not report attacks), Vikings were busy in Scotland, while Colmán Etchingham (1996), based on more recent evidence, has disputed the notion that the lack of chroniclers’ reports necessarily reflects a hiatus in raiding in Ireland for those years. From the mid-830s, Viking activities entered a third phase: larger armies attacked Ireland, England, and Francia, penetrated inland, and in some cases began overwintering.
There is little Insular or Continental evidence as to where in Scandinavia the ship crews of the pre-mid-830s raids originated; the information in the Anglo-Saxon Chronicle that the ships in Portland 789 came from Hordaland is an addition to the chronicle a century after the event (Downham 2017) and thus less reliable. The origin of the culprits in the early raiding in northern Great Britain and Ireland, however, is indicated by Scandinavian evidence. Except for a single piece in eastern Agder, the buried Insular loot from around 800 or slightly earlier has been retrieved solely in the five neighbouring regions of northern Hordaland, Sogn, Nordfjord, Møre, and Trøndelag (Fig. 8; Wamers 1985:49–56). Admittedly, such items may already have been old when taken, and burial customs in southern Scandinavia provide a meagre basis for quantitative comparison with those of the western Scandinavian Peninsula. Still, the distinct concentration of the earliest loot within a rather narrow area instils confidence in the conclusion that most raiding into Scottish and Irish waters in the pre-806 phase, possibly also somewhat later, emanated from these few regions on the west-Scandinavian coast (Ó Corráin 1998:1–2; Wamers 1985:85; Williams 2008:193). From Heen-Pettersen’s (2014) analysis of the Trøndelag finds it appears that the earliest raids were organised from prominent and well-established aristocratic manors.
No such find patterns can guide the search for the origin of the early raiders in England and Francia, but western and southern Scandinavia is a safe bet. The royal power that emerged in southern and western Scandinavia in the late eighth century will have had two effects, both of which produced redundant military capacity. Firstly, royal power would have subdued rivalry between smaller polities and among royal pretenders, and leaders previously engaged in such unrest will have been ready to direct their troops elsewhere. Secondly, royal power provided safe sailing for traders, thus reducing spoils and increasing risks for Vikings who previously had parasitized on traders. Some of this excess military capacity may have joined a king’s retinue or taken up long-distance trade. However, the latter enterprise was available only for those who produced or had access to commodities that were in demand overseas. For those who lacked access to such goods or were not involved in the protection of the sailing route, there were few alternatives to taking up plunder in new waters if they hoped to partake of the benefits enjoyed by their peers among traders and in the king’s service.
Once rising royal power put the damper on raiding close to home, warriors and ship commanders in southern and western Scandinavia would have looked overseas for alternative hunting grounds. Through several generations’ recurring trade ventures in the southern North Sea zone, Scandinavians would have collected knowledge from traders and sailors of lands and waters in all the areas affected by the earliest raids—details would have been extracted from captives taken en route.
Why, then, was raiding c. 806–35 concentrated in Ireland and Scotland? Hypothetically, resistance was weaker there. Elsewhere, Vikings may have been put off by defensive measures, for instance by Offa’s upholding in 792 of the obligation of churches and monasteries in Kent to contribute to the defence ‘against seaborne pagans with migrating fleets’ (Downham 2017:5), by the alleged slaughter of 105 of the Paganae vero naves that attacked Aquitaine in 799, and by Charlemagne’s building of a fleet and establishment of watch posts in 800 to defend against pirates that troubled the sea outside Gaul (Walther 2004:168–169). However, on several occasions in Ireland, efficient and successful resistance was indeed mustered (Ó Corráin 1998); a more complex background for the concentration of Viking activities to Ireland and Scotland must be sought.
Another contributing factor to the three decades’ confinement of Viking raiding to Ireland and Scotland is that raiding there did not interfere with the prosperous trade in the southern North Sea zone and the English Channel. Royal peacekeepers and traders along the Norðvegr and in southern Scandinavia would have had an interest in preventing raids in the lands and waters where they traded; that Vikings in this period returned to the homelands each year kept them within reach of royal power and aristocratic traders.
In an abrupt shift in the mid-830s, extensive Viking raiding commenced in England and in the Empire. Unprecedented in magnitude, this wave of raiding has been considered to have dealt a blow to craft production and trade in those countries. Dorestad was sacked in 834 and annually again for three consecutive years. The internal disputes between Louis the Pious and his rebellious sons in the early 830s and among his sons following his death 840 left the Empire vulnerable. For several decades, coasts and riverbanks from Frisia to Bordeaux were heavily and repeatedly sacked (Nelson 1997; Walther 2004:171–177). In England a large army landed in 835 on Isle of Sheppey in the Thames Estuary, heralding several decades of intense raiding in England, targeting towns (Southampton in 840 and 842, London in 851), culminating in the invasion in 865 of the Great Heathen Army that ravaged eastern and northern England for more than a decade.
How did the interests of Vikings come to eclipse those of Scandinavian traders in the mid-830s? This is a complex issue and we will restrict the discussion to suggesting some factors that may have contributed to these developments. As a prelude, the question of precisely how harmful Viking raids were to trade needs to be weighed. Hodges (2006:157–162) has downplayed the significance of raids, arguing that in the 830s, trade in the southern North Sea zone was already dwindling, while Dorestad, London, and Southampton were in recession; thus, Viking attacks were not the main reason for the slump in trade and the abandonment of towns around 850. However, the archaeological evidence he refers to is not dated with sufficient precision to determine whether the recession began before, during, or after the 830s. The trade in Arctic commodities in Ribe appears to have remained on a consistently high level even in the town’s final phase in 820–50; there is no indication of Hodges’ suggested pre-830s recession. When production and trade in Ribe dwindled, this was probably due to the breaking of trade connections to the south and west, particularly to Dorestad. Clearly, Hodges is right that the recession in Carolingian economy in the mid-800s has a complex background, but his reasons for minimizing the impact of Viking attacks on this development do not seem convincing.
Trade in the Baltic prospered in these years as the eastern riverine routes towards the Finns, Slavs, Kahzars, Bulgars, Arabs, and others opened, and urban sites in the Baltic flourished (Callmer 2007). Kaupang’s trade links to the southern North Sea zone were broken off c. 850, probably because trade in Ribe and Dorestad tailed off. Contemporaneously, brooch types from the west-Scandinavian coast, which did not occur at Kaupang in the early ninth century, began to predominate in cemeteries there. Evidently, trade routes along the western coast of the Scandinavian Peninsula shifted from the North Sea zone to Skagerrak, Kattegat (Skre 2011b), and the Baltic (Skre 2018c:15)—the very route followed by Ohthere.
In view of the above, it seems likely that the Viking raids in England and the Empire from the mid-830s were detrimental to trade in the southern North Sea zone, and were thus contrary to the interests of kings and traders in western and southern Scandinavia. Why, then, were they not stopped?
Firstly, the Danish King Horik’s message to the Emperor that he had captured and killed those who had raided Frisia in 836 (Nelson 1997:24) indicates that royal attempts to quell overseas raiding were in fact being undertaken. The battle against returning Vikings that led to Horik’s death in 854 may have resulted from such controversies. Secondly, the motivation on the part of Scandinavian kings and traders to stop Viking raids in the North Sea may have been undercut by the viable alternative in the Baltic trade. Thirdly, and possibly most importantly, Vikings gained much greater independence from kings and traders when they began overwintering overseas in the mid-830s; they were less dependent on frið in the homelands and were out of reach for kings and traders based there, hence more difficult to subdue.
In parallel, there is potentially a ‘pull’ factor behind overwintering overseas. While the first fleets that ravaged Ireland were small, the two fleets that entered the Liffy and the Boyne in 837 were each composed of 60 ships and carried a total of some 3000 men (Ó Corráin 2008:429). Kurrild-Klitgaard and Svensen (2003) hold that because successful raiding attracts other pirates over time, the success of roving raiders produces a ‘common pool resource problem’, reducing the share of spoils for all raiders. When proceeds decrease below an acceptable level, one solution would be to establish a settlement in the vicinity of the potential loot so as to exclude others from raiding in the surrounding territory. While Kurrild-Klitgaard and Svensen see this as the logic behind state formation and taxation, it may equally well contribute to explaining the two shifts in Viking behaviour in the mid-830s: the start of overwintering and the taking up of raiding in England and the Empire. The motif of establishing well-defended longphuirt in Ireland (Sheehan 2008) may not have been to protect only against the Irish but also against other Vikings who sought to obtain spoils from the region. Thus, defended Viking bases in Ireland and Scotland may have compelled latecoming Viking-ship commanders to look elsewhere for prey. As the numbers of Vikings increased, attacks on prosperous towns and regions in southern England and Francia became realistic ventures. Large fleets that could undertake such operations were formed through agreements between ship commanders, possibly up to 50, each in command of only a few ships (Price 2016:164). Drawing on parallels to seventeenth to eighteenth century piracy, Price (2014; 2016) uses the term hydrarchy to characterise this distinctive Viking strategy of joining and splitting up forces depending on the target’s strength. It ensured that satisfactory proceeds for all raiders could be obtained from a large force’s attack on a well-defended town as well as from a small unit’s pillaging of a less rich and less protected monastery or settlement.
The earliest record of overwintering refers to Ireland in 836, the first in the Empire at Noirmoutier Island off Aquitaine in 843, and in England on Thanet Island in Kent in 850. However, all these instances may have been preceded by overwintering in Scotland. Permanent Viking camps in Scotland, possibly also in Ireland, appear to have been the bases from which many of the subsequent raids set out for England and the Empire, not to mention for occasional raids against the west-Scandinavian coast. The paucity on the western coast of the Scandinavia Peninsula of Frankish and south-Anglo-Saxon buried loot as compared to Northumbrian, Scottish, and Irish loot suggests that few of those who pillaged in the south returned to the western coast of the Scandinavian Peninsula, and conversely that some of those who pillaged in the north did return to the homelands.
Irish annals mention no kings among the Vikings until 848, after which their deeds were mentioned on several occasions. Their main mission, it seems, was not primarily to raid the Irish, but to assert control over the Vikings who were already based there (Ó Corráin 1998). There has been a lengthy debate as to where these kings ruled—their land is called Laithlinn—in Scotland (Ó Corráin 1998) or in what later became Norway (Etchingham 2014). That question is connected to the debate on the origin and nature of two groups of foreigners identified in the annals in these years, the Finngall (‘fair’) and the Dubgall (‘dark’); the latter arrived to attack former (Downham 2011). While this discussion involves intricate philological and historical problems that will not be addressed here, we suggest that the conflicting interests of overwintering Vikings on the one hand and west-Scandinavian traders and royal peacekeepers on the other may be of relevance for these debates.