For other uses of the word thrall, see Thrall (disambiguation)

Thrall (Thræl for men, Thír for women) was the Scandinavian name for slave during the Viking Age. Slavery was one of the primary sources of income for the Vikings, and the word Slave is connected to the fact that most of the slaves came from the Slavic territories in Eastern Europe. The first person to describe thralls was the Roman historian Tacitus, in 98 AD, who wrote that the Swedes (Suiones) had no right to carry arms, but that the weapons were locked inside and protected by a slave only to be distributed when they were attacked by enemies.

The system was supported by Norse mythology which claimed that the thralls had a separate ancestry through Ríg.

A person could become a thrall by giving up himself because of starvation and this was considered to be the most shameful way of entering slavery and the manner which was the first to be forbidden. The most common manner of acquiring thralls was to capture people in foreign countries or by buying such thralls.

The thralls were kept as livestock and their master had the right of their life and death. The one who was born of a female thrall, by a free father was considered to be a thrall, whereas those who were born by a free woman having a thrall father were considered to be free. Some thralls had higher status and were called Brytes .

When Christianity arrived in Northern Europe, there was increasing demand for non-Christian slaves, and the Scandinavians had a de facto monopoly on trading with them since Christians were not allowed to trade with slaves.

As Scandinavia was christianized, slavery became unfashionable and since the owners were obliged to support aged thralls, the system was transformed into serfdom.