In 1526, all of Silesia, including Świdnica (as "Schweidnitz"), came under the rule of the Habsburg Monarchy as part of the surrounding Duchy of Schweidnitz. In the 16th century it was one of the regional centers of Anabaptism. The city suffered greatly during the Thirty Years' War (1618–48) as a result of sieges, fires and epidemics. Schweidnitz was annexed by the Kingdom of Prussia during the First Silesian War (1740–42). The town was turned into a fortress, which it remained until 1866.