The 11th Army was formed in early 1915. It briefly fought on the Western Front during the Battle of Ypres, holding the line against the Allied attack. On 22 April, it was transferred and placed with the Austrian 4th Army under Mackensen's command, behind the Gorlice–Tarnow gap, south of the Vistula River. In July 1915, the 11th Army advanced into Russian territory in a general German offensive. The 11th Army was dissolved on 8 September 1915.