 Complete the following phrase:  The 12th Panzer Division participated in Operation Barbarossa, taking part in the drive towards Leningrad. Suffering heavy casualties during the Soviet counter offensive in the winter of 194142, the division was withdrawn to Estonia for a refit. It remained with Army Group North for the most part of the war except for a brief spell south while participating in the battle of Kursk in July 1943 and the following defensive operations and retreat after the German failure. The division returned to the northern sector in January 1944 but came too late to play any role in the unsuccessful German efforts to prevent the Siege of Leningrad from being broken by the Red Army. It was eventually entrapped in the Courland Pocket after the successful Soviet offensive in July 1944, 