Interracial marriage
From AD 839, Viking Varangian mercenaries who were in the service of the Byzantine Empire, notably Harald Sigurdsson, campaigned in North Africa, Jerusalem and other places in the Middle East during the Byzantine-Arab Wars. They interbred with the local population as spoils of warfare or through eventual settling with many Scandinavian Viking men taking Arab or Anatolian women as wives. There is archaeological evidence the Vikings had established contact with the city of Baghdad, at the time the center of the Islamic Empire, and connected with the populace there. Regularly plying the Volga with their trade goods (furs, tusks, seal fat, seal boats and notably female slaves; the one period in the history of the slave-trade when females were priced higher than males), the Vikings were active in the Arab slave trade at the time. These slaves, most often Europeans that were captured from the coasts of Europe or during war periods, and sold to Arabic traders in Al-Andalus and the Emirate of Sicily.
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.