Margraviate of Meissen
He was the eldest son of Frederick III, Landgrave of Thuringia, and Catherine of Henneberg. After the death of his uncle William I, Margrave of Meissen in 1407, he was made governor of the Margraviate of Meissen together with his brother William II as well as with his cousin Frederick IV (son of Balthasar), until their possessions were divided in 1410 and 1415.