Career
When Margrave William I "the one-eyed" died in 1407, William and Frederick also inherited a part of Meissen. Under the 1410 Treaty of Naumburg, however, the brothers agreed to a fresh division of the Meissen territory. They agreed to divide the Osterland between themselves.
They did so in 1411.
William received the larger part of the Osterland, including Leipzig, which Frederick had managed to obtain instead of Jena. He is rumoured to have been married to Amelia of Mazovia. He died on 13 March 1425.