With his father, he was excommunicated by the Pope Pius II for not to support the eventual inheritance of Casimir IV's son over the Bohemia throne.
Since the beginning of his reign, Henry XI continued his father's politics, for example, when he successfully supported his cousin Balthasar in his attempt to recover the Duchy of Żagań after being deposed by his brother Jan II the Mad in 1468.
One year later, during King Matthias's coronation as King of Bohemia at Olomouc, he received the formal restoration of the lands belonged to the Duchy of Głogów who were annexed by the Kingdom of Bohemia since 1360 (including the other half of Głogów), but he only could take formal possession after the death of Margareta of Celje (widow of Duke Władysław, from the Cieszyn branch), who held the cities as her dower.
The next legitimate male heir of Henry XI was his cousin Jan II the Mad, former Duke of Żagań, who had to face the pretensions of the Elector of Brandenburg, Matthias Corvinus and the King of Poland.
Only in 1482 was finally made an arrangement in Kamieniec Ząbkowicki, under which the towns of Krosno Odrzańskie, Sulechów, Lubsko, Bobrowice passed to Brandenburg.