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.
Horik II
During Horik's reign, Vikings raided England in 855 and 860 with varying success. The Great Heathen Army arrived to East Anglia in 865 and conquered York in Northumbria two years later, starting the Viking conquest and colonization of much of northeast England. While they are expressly called Danes in the Anglo-Saxon Chronicle, the army appears to have been formed by Vikings operating in Francia and Frisia. Whether the royal power in Denmark had part in the planning and organization is unknown. Later sagas assert that this was the case, depicting the leaders of the invasion as sons of the Danish king Ragnar Lodbrok. However, no such king is known in the contemporary sources. The invasion leaders Halfdan and Bagsecg were known as "kings" and may or may not have been related to the kings in the Danish homeland.