ful political organization in Europe since the Roman Empire, may in some sense have initiated the Viking expansion, if only by stimulating trade and thus giving the opportunity for piracy.

In the 790s both Charlemagne and King Offa of Mercia were organizing coastal defences against the Vikings. But the first recorded attacks were further north, on three of the most famous northern monasteries: Lindisfarne ( 793), Jarrow ( 794), and Iona ( 795). Recorded attacks are not the same thing as attacks, of course; to be recorded means a nearby monastery to mention the attack in its annals, and a monastery which subsequently survived, thus preserving the record. Few records of attacks survive from Northumbria: the attacks were so sustained that, in the course of the early ninth century, monasticism became virtually extinct and monastic libraries almost totally destroyed. On the other hand, large numbers of attacks are recorded on Irish monasteries: Irish monastic annals provide us with very detailed records, and the monasteries mostly survived the attacks.

The earliest raids were carried out by small numbers of ships, and never penetrated far inland. It was not until the 830s that more large-scale raids were organized, taking advantage of knowledge gained earlier and, in Francia, taking advantage of the political troubles of Louis the Pious. Dorestad was raided three times between 834 and 836. Raids reached right into central Ireland, and forced the monks of the island monasteries of Lindisfarne and Noirmoutier (by the mouth of the Loire) to move themselves and their relics further inland. Viking fleets wintered for the first time in Ireland in 840/1, and founded permanent settlements, including Dublin. The first wintering in France was at Noirmoutier in 843; in 851 the Vikings wintered in southern England, on Thanet.

The raiding Vikings seem to have been sensitive to changing circumstances, moving to the area of northern Europe which could offer the most profit, in booty or in tribute. Louis the Pious built coastal forts and reorganized his fleet in the late 830s, and the Vikings began attacking the southern English coast. On the death of Louis the Pious in 840 there was civil war in Francia, and the Vikings sailed up the Seine in 841

-101-