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.
Swedes
During the early stages of the Scandinavian Viking Age, Ystad in Scania and Paviken on Gotland, in present-day Sweden, were flourishing trade centres. Remains of what is believed to have been a large market have been found in Ystad dating from 600–700 AD. In Paviken, an important centre of trade in the Baltic region during the 9th and 10th centuries, remains have been found of a large Viking Age harbour with shipbuilding yards and handicraft industries. Between 800 and 1000, trade brought an abundance of silver to Gotland, and according to some scholars, the Gotlanders of this era hoarded more silver than the rest of the population of Scandinavia combined.