even though Scandinavian coastal raids on England and the Continent were recorded long before the eighth century, the attacks which began in the 790s were perceived by contemporaries as something new in their nature, scope and extent. Over the next 120 years these Scandinavian incursions would increase to such a pitch that they would threaten to overwhelm the Anglo-Saxon and West Frankish kingdoms, and ultimately leave an enduring mark in the form of the settlement of Normandy and the Danelaw.

The first wave of attacks offered only a hint of what was to come. From the first raids in the 790s until 840, the sources record only small Viking fleets making hit-and-run attacks along the coast. The Viking longships with their shallow draught were ideally suited to surprise raids on coastal locations, being uniquely able to land raiding parties close to poorly defended monasteries or trading centres, then to row away as swiftly as they had come. Against this new form of warfare the Franks and Anglo-Saxons had little defence.

Two areas of the Carolingian empire came under attack at this time: Frisia, where the culprits were Danes, making their way south along the Frankish coast, and Aquitaine, where the raiders were probably Norwegians coming from Ireland, which suffered a wave of Norse invasions in the early ninth century (Map 13). Information about the raids on Aquitaine is sparse, primarily because most of the longer annals were written in the north of the empire. Nonetheless, local sources reveal a continuing Scandinavian menace throughout the early years of the ninth century.