Due to a rapid German offensive, the Corps retreated towards the Dniepr river. Near the town of Kaniv, German and Austrian forces surrounded the Poles, who were commanded by General Józef Haller. After the Battle of Kaniów (May 10–11, 1918), the Corps capitulated on May 12, and Polish soldiers were disarmed and taken into captivity. Those who had served in the Legions were regarded as traitors and most of them were imprisoned in Parchim, Mecklenburg, they were kept there until November 1918.