United Duchies of Jülich-Cleves-Berg
Its history is closely related to that of its neighbours: the Duchies of Jülich, Berg and Guelders and the County of Mark. In 1368, Cleves and Mark were united. In 1521 Jülich, Berg, Cleves and Mark formed the United Duchies of Jülich-Cleves-Berg. The territory was situated on both sides of the river Rhine, around its capital Cleves and roughly covering today's districts of Cleves, Wesel and the city of Duisburg. He was succeeded by his son Arnold I, Count of Cleves.