Friedrich IV., was Margrave of Meissen and as Friedrich I. Elector of Saxony (Frederick the Belligerent or the Warlike) from 1381 until his death. He is not to be confused with his cousin Frederick IV, Landgrave of Thuringia, the son of Balthasar, Landgrave of Thuringia. Frederick the Warlike was never Landgrave of Thuringia.
Married on February 8th, 1402 to Katherina von Braunschweig, daughter of Henry the Mild, Duke of Braunschweig-Lüneburg, they had 7 children.
Katharina von Braunschweig-Lüneburg