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.
Viking Age
The term Varangian remained in usage in the Byzantine Empire until the 13th century, largely disconnected from its Scandinavian roots by then.
Having settled Aldeigja (Ladoga) in the 750s, Scandinavian colonists were probably an element in the early ethnogenesis of the Rus' people, and likely played a role in the formation of the Rus' Khaganate. The Varangians (Varyags, in Old East Slavic) are first mentioned by the Primary Chronicle as having exacted tribute from the Slavic and Finnic tribes in 859. It was the time of rapid expansion of the Vikings in Northern Europe; England began to pay Danegeld in 859, and the Curonians of Grobin faced an invasion by the Swedes at about the same date.
In 862, the Finnic and Slavic tribes rebelled against the Varangian Rus, driving them overseas back to Scandinavia, but soon started to conflict with each other. The disorder prompted the tribes to invite back the Varangian Rus "to come and rule them" and bring peace to the region. This was a somewhat bilateral relation with the Varagians defending the cities that they ruled. Led by Rurik and his brothers Truvor and Sineus, the invited Varangians (called Rus') settled around the town of Novgorod (Holmgard).