His successor, Dietrich II of Moers witnessed the last attempts by Cologne to gain rulership in Westphalia by attempting to break the powerful positions of Cleves and Marck. The financial burden placed upon the knights and cities of the Duchy of Westphalia led them into union in 1437. Cologne made peace with Cleves in 1441: this led Soest, the richest town of Westphalia, to refuse recognising Colognian supremacy in 1444 in the Soest Feud, that lasted until 1449.
Dietrich II of Moers succeeded his predecessor and witnessed Cologne's attempts to gain control over Westphalia by challenging Cleves and Marck. The financial burden on the knights and cities of the Duchy of Westphalia led them to unite in 1437.  Cologne made peace with Cleves in 1441, which prompted Soest, the wealthiest town in Westphalia, to reject Cologne's authority in 1444 during the Soest Feud, which lasted until 1449.