Upon his father's death in 1360, William became Count of Berg and Ravensberg, a title that his father had gained by marrying the heiress of Berg and Ravensberg. In 1380, King Wenzel elevated him to the rank of Duke, thus becoming the first Duke of Berg.
William fought the counties of Mark and Cleves to prevent them from combining but in 1397 he was taken prisoner in the battle of Kleverhamm. He lost Remagen, Kaiserwerth and Sinzig to his nephew Adolf IV, Count of Kleve-Mark and due to these losses, his sons turned against him and imprisoned him in 1403/04. He ultimately forced them to submit and later supported his brother-in-law Rupert, King of Germany against Guelders-Jülich and won the county of Blankenburg. William died on 25 June 1408 and is buried in the Abteikirche in Altenberg.
Family and children
On 28 September 1363, William married Anna of the Palatinate (1346 – 30 November 1415), daughter of Rupert II, Elector Palatine and Beatrice of Sicily. They had the following children:
