Vikings in Iberia
The first incursion of the Vikings in Iberia has been characterised as 'probably the most significant episode of the whole period of Viking activity in the South'. It is mentioned in "Annales Bertiniani", and dated August 844, when a group from a plundering expedition entered the Garonne and reached Galicia. Despite storm damage, some proceeded to South-West Spain. This account is consistent with several later, but independent sources in Latin and Arabic. In particular, the late ninth- or early tenth-century "Chronicle of Alfonso III" adds that after plundering a number of coastal villages they were ultimately repulsed in the vicinity of "Farum Brecantium" (i.e. the Tower of Hercules). Ramiro I of Asturias gathered troops in Galicia and Asturia for the counter-attack. After the Asturian victory, the Vikings continued their voyage in direction of Lisbon. While some authors consider that the reliability of this chronicle is open to doubt, others consider that other local chronicles confirm the arrival of the Norsemen.
Ímar
Norse contact with Scotland predates the first written records in the 8th century, although the nature and frequency of these contacts is unknown. Excavations on the island of Unst in Shetland indicate that Scandinavian settlers had reached there perhaps as early as the mid-7th century and from 793 onwards repeated raids by Vikings on the British Isles are recorded. "All the islands of Britain" were devastated in 794 with Iona being sacked in 802 and 806. The Frankish "" may record the conquest of the Inner Hebrides by Vikings in 847. Scholarly interpretations of the period "have led to widely divergent reconstructions of Viking Age Scotland", especially in the early period, and Barrett has identified several competing theories, none of which he regards as proven. Ó Corráin notes: "when and how the Vikings conquered and occupied the Isles is unknown, perhaps unknowable".