During World War II, the Soviet State Committee of Defence and the General Staff of the Red Army were located in Moscow. In 1941, 16 divisions of the national volunteers (more than 160,000 people), 25 battalions (18,000 people), and four engineering regiments were formed among the Muscovites. Between October 1941 and January 1942, the German Army Group Centre was stopped at the outskirts of the city and then driven off in the course of the Battle of Moscow. Many factories were evacuated, together with much of the government, and from October 20 the city was declared to be in a state of siege. Its remaining inhabitants built and manned antitank defenses, while the city was bombarded from the air. On May 1, 1944, a medal "For the defence of Moscow" and in 1947 another medal "In memory of the 800th anniversary of Moscow" was instituted.