Duchy of Głogów
In 1480 Jan II attempted to unify Głogów (the Duchy was divided in two parts, one belonged to him, and the other, which previously belonged to the Cieszyn branch, was now in power of the Bohemian Kingdom). After a siege of seven weeks, on 1 May 1480 the city was conquered and the Duchy of Głogów was finally reunited after almost 150 years of separation.