The Siege of Dunkirk in World War II occurred from September 1944 when units of the Second Canadian Division surrounded the heavily fortified city and port of Dunkirk. German units within the fortress withstood initial probing attacks, and as the opening of the port of Antwerp became a higher priority, the Allied commander, Montgomery, decided to merely contain the Germans within Dunkirk without attacking the fortified city. For this task, the 1st Czechoslovak Armoured Brigade was used. The German garrison remained in Dunkirk until the general German surrender in May 1945. In so doing, the garrison denied the Allies the use of the port. The fortress, commanded by Admiral Friedrich Frisius, eventually surrendered unconditionally to Brigade General Alois Liška, the commander of the Czechoslo