Duchy of Legnica
Wąsosz dates back to the medieval Piast-ruled Kingdom of Poland and its name is of Polish origin. It was granted town rights by Henry III, Duke of Głogów in 1290. It was part of the Duchy of Głogów of fragmented Poland and in the 14th century the local castle of the Piast dukes was built. The castle was unsuccessfully besieged by the Hussites in 1432. In 1520 Wąsosz passed to the bishops of Wrocław and in 1525 it passed again under Piast rule as part of the Duchy of Legnica.