A medieval Arab historian estimates that 200,000 women and children were taken as slaves after the Byzantine reconquest of Crete from the Muslims.[1] Yet parents, living in the Byzantine empire, were forced to sell their children to pay their debts, which Byzantine laws unsuccessfully tried to prevent.[5] After the 10th century the major source of slaves were often Slavs and Bulgars,[9] which resulted from campaigns in the Balkans and lands north of the Black Sea.[10] At the eastern shore of the Adriatic many Slav slaves were exported to other parts of Europe.[10] Slaves were one of the main articles that Russian (often Vikings) traders dealt in their yearly visit to Constantinople.