Silesia , Polish Śląsk German Schlesien, Historic region, east-central Europe. It now lies mainly in southwestern Poland, with parts in Germany and the Czech Republic. It was originally a Polish province that became a possession of the Bohemian crown, and thus part of the Holy Roman Empire, in 1335. Because of succession disputes and the region’s prosperity, there were at least 16 Silesian principalities by the end of the 15th century. It passed to the Austrian Habsburgs in 1526; it was taken by Prussia in 1742. After World War I it was divided between Poland, Czechoslovakia, and Germany. During World War II Polish Silesia was occupied by Germany and was the site of atrocities against the population by Nazi and, later, Soviet forces. In 1945 the Allied powers assigned virtually all of Silesia to Poland; today its nine Polish provinces contain almost one-fourth of Poland’s population.
