In a feud between Edward of Guelders, who was a son of Duke Reginald II and adversary of his elder brother, Reginald III, Count Engelbert III of the Mark conquered the now insufficiently fortified town in 1371 and partly destroyed it. The childless Edward fell in the same year on the battlefield of Baesweiler fighting on the side of his brother in law, Duke William II of Jülich, against Duke Wenceslaus I of Brabant. When in that year his brother, Rainald III, also died without issue, fighting broke out repeatedly over the inheritance and possession of the Duchy of Guelders under which Erkelenz, as an exclave of Guelders in the state of Jülich, suffered particularly severely from the burdens of war, quartering of soldiers, robbery and plundering.