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.
Vikings
The majority of runic inscriptions from the Viking period are found in Sweden and date from the 11th century. The oldest stone with runic inscriptions was found in Norway and dates to the 4th century, suggesting that runic inscriptions pre-date the Viking period. Many runestones in Scandinavia record the names of participants in Viking expeditions, such as the Kjula runestone that tells of extensive warfare in Western Europe and the Turinge Runestone, which tells of a war band in Eastern Europe. Other runestones mention men who died on Viking expeditions. Among them are around 25 Ingvar runestones in the Mälardalen district of Sweden, erected to commemorate members of a disastrous expedition into present-day Russia in the early 11th century. Runestones are important sources in the study of Norse society and early medieval Scandinavia, not only of the Viking segment of the population.