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.
Viking Age
The earliest date given for a Viking raid is 789, when according to the "Anglo-Saxon Chronicle", a group of men from Norway sailed to the Isle of Portland in Dorset (it was wrongly recorded as 787). They were mistaken for merchants by a royal official. When asked to come to the king's manor to pay a trading tax on their goods, they murdered the official. The beginning of the Viking Age in the British Isles is often set at 793. It was recorded in the "Anglo–Saxon Chronicle" that the Northmen raided the important island monastery of Lindisfarne (the generally accepted date is actually 8 June, not January):