Slavery, or the ownership of persons who are deemed property, was widespread within medieval Europe. Europe and the Mediterranean world during the medieval period (500–1500) were part of a highly interconnected network of slave trading. Throughout Europe, wartime captives were commonly forced into slavery. As European kingdoms transitioned to feudal societies, serfdom began to replace slavery as the main economic and agricultural engine. Throughout medieval Europe, the perspectives and societal roles of enslaved peoples differed greatly, from some being restricted to agricultural labor to others being positioned as trusted political advisors.
Early Middle Ages
Slavery in the Early Middle Ages (500–1000) was initially a continuation of earlier Roman practices from late antiquity, and was continued by an influx of captives in the wake of the social chaos caused by the barbarian invasions of the Western Roman Empire. With the continuation of Roman legal practices of slavery, new laws and practices concerning slavery spread throughout Europe. For example, the Welsh laws of Hywel the Good included provisions dealing with slaves. In the Germanic realms, laws instituted the enslavement of criminals, such as the Visigothic Code’s prescribing enslavement for criminals who could not pay financial penalties for their crimes and as an actual punishment for various other crimes. Such criminals would become slaves to their victims, often with their property.
As these peoples Christianized, the church worked more actively to reduce the practice of holding coreligionists in bondage. St. Patrick, who himself was captured and enslaved at one time, protested an attack that enslaved newly baptized Christians in his letter to the soldiers of Coroticus. The restoration of order and the growing power of the church slowly transmuted the late Roman slave system of Diocletian into serfdom.
Another major factor was the rise of Bathilde (626–680), queen of the Franks, who had been enslaved before marrying Clovis II. When she became regent, her government outlawed slave-trading of Christians throughout the Merovingian empire. About ten percent of England’s population entered in the Domesday Book (1086) were slaves, despite chattel slavery of English Christians being nominally discontinued after the 1066 conquest. It is difficult to be certain about slave numbers, however, since the old Roman word for slave (servus) continued to be applied to unfree people whose status later was reflected by the term serf.
Slave trade
Demand from the Islamic world, which arose in the seventh century, dominated the slave trade in Europe during the medieval period (500–1500). For most of that time, the sale of Christian slaves to non-Christians was banned. In the pactum Lotharii of 840 between Venice and the Carolingian Empire, Venice promised not to buy Christian slaves in the Empire, and not to sell Christian slaves to Muslims. The Church prohibited the export of Christian slaves to non-Christian lands, for example in the Council of Koblenz in 922, the Council of London in 1102, and the Council of Armagh in 1171.
As a result, most Christian slave merchants focused on moving slaves from non-Christian areas to Muslim Spain, North Africa, and the Middle East; and most non-Christian merchants, although not bound by the Church’s rules, focused on Muslim markets as well. Arabic silver dirhams, presumably exchanged for slaves, are plentiful in eastern Europe and Southern Sweden, indicating trade routes from Slavic to Muslim territory.
Italian merchants
By the reign of Pope Zachary (741–752), Venice had established a thriving slave trade, enslaving people in Italy, among other places, and selling them to the Moors in Northern Africa (Zacharias himself reportedly forbade such traffic out of Rome). When the sale of Christians to Muslims was banned (pactum Lotharii), the Venetians began to sell Slavs and other Eastern European non-Christian slaves in greater numbers. Caravans of slaves traveled from Eastern Europe, through Alpine passes in Austria, to reach Venice. A record of tolls paid in Raffelstetten (903–906), near St. Florian on the Danube, describes such merchants. Some are Slavic themselves, from Bohemia and the Kievan Rus'. They had come from Kiev through Przemyśl, Kraków, Prague, and Bohemia. The same record values female slaves at a tremissa (about 1.5 grams of gold or roughly of a Byzantine solidus (nomisma) or Islamic gold dinar) and male slaves, who were more numerous, at a saiga (which is much less). Eunuchs were especially valuable, and "castration houses" arose in Venice, as well as other prominent slave markets, to meet this demand.