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.
Vikings
A consequence of the available written sources, which may have coloured how the Viking age is perceived as a historical period, is that much more is known of the Vikings' activities in western Europe than in the East. One reason is that the cultures of north-eastern Europe at the time were non-literate, and did not produce a legacy of literature. Another is that the vast majority of written sources on Scandinavia in the Viking Age come from Iceland, a nation originally settled by Norwegian colonists. As a result, there is much more material from the Viking Age about Norway than Sweden, which apart from many runic inscriptions, has almost no written sources from the early Middle Ages.