Duchy of Legnica
Since the beginning of his reign he sided against the rule of Emperor Charles V, joined to the Coalition of Protestant rebel princes and made an alliance with the long-time enemy of the Habsburgs, King Henry II of France. This behavior motivated the invasion of Charles V to the Duchy of Legnica and the formal deposition of Frederick III in 1551. His eldest son Henry XI was made new Duke, but, still a minor, was cared under the regency of his uncle George II of Brzeg.