After they came of age, William and Balthasar ruled jointly with Frederick.

After Frederick's death, a conflict arose between the brothers Balthasar and William on the one hand, and their nephews, Frederick the Warlike, William the rich and George on the other hand.

This was resolved on November 1382, with the so-called Division of Chemnitz in which Balthasar received the Landgraviate of Thuringia.

Balthasar first married, in the spring of 1374, with Margaret, the daughter of Burgrave Albert of Nuremberg (d. 1390).

With her, he had a son and a daughter: After Margaret's death, Balthasar married Anna of Saxe-Wittenberg (d. 1426), the widow of Duke Frederick I of Brunswick-Lüneburg.