Denmark attacked Swedish dominions in Germany in 1657. This meant that the Swedish army, including the forces under Ascheberg's command, left Poland to instead engage their Danish enemy. In 1658, Ascheberg spearheaded the March across the Belts as the Swedish army marched across the ices of Little Belt and Great Belt in order to reach the Danish island of Zealand. He narrowly escaped being caught when the enemy under Frederick William of Brandenburg and Polish commander Stefan Czarniecki attacked Sønderborg in December 1658. In February 1659, he was badly wounded during the assault on Copenhagen. After spending 10 weeks abed, a recovered von Ascheberg returned to the battlefield in time to be in charge of the conquest of the island Møn in May 1659. He remained on the island until the war ended in 1660.