Adolf IX of Berg

Adolf was an important and loyal supporter of Ludwig IV of Bavaria, helping him since 1314 in the war of succession.

As a result of Adolf's 1312 marriage to Agnes of Cleves, he received the Rhine customs of Duisburg as a dowry and these were confirmed as an imperial fief by Emperor Louis in 1314.

He continued the constant feuds between the House of Berg and the Archbishops of Cologne.

In 1337 Adolf joined the English-German Alliance which caused the start of the Hundred Years' War.

He died on 3 April 1348 without children and was succeeded by his only surviving niece, Margaret of Ravensberg by right of her mother, and her husband Gerhard VI of Jülich as Count and Countess of Berg.