Background
William was the son of Gerhard VII, Duke of Jülich-Berg and Sophie of Saxe-Lauenburg. When his father died in 1475, William became Duke of Jülich-Berg.
William was the son of Gerhard VII, Duke of Jülich-Berg and Sophie of Saxe-Lauenburg. When his father died in 1475, William became Duke of Jülich-Berg.
In 1481, William remarried with Sibylle of Brandenburg, daughter of Albert III Achilles, Elector of Brandenburg. Neither marriage produced a son, so the succession of the Duchy became a problem. William then concluded in 1496 the Klever Union with John II, Duke of Cleves, in which the union of the Duchy of Jülich-Berg and the Duchy of Cleves-Mark was planned.
William had only one five-year-old daughter, Maria, who was promised in marriage to John II"s six-year-old son John III. He is buried in Altenberg Abbey.
John III then became the first ruler of the United Duchies of Jülich-Cleves-Berg, which would exist until 1666.