Among these were 19 panzer divisions, and in total the “Barbarossa” force had about 3,000 tanks, 7,000 artillery pieces, and 2,500 aircraft. German-Soviet Nonaggression Pact, pact signed on August 23, 1939, between Germany and the Soviet Union that was concluded a few days before the beginning of World War II and which divided eastern Europe into German and Soviet spheres of influence. Invasion of the Soviet Union, 1941. The pact was voided when Germany launched Operation Barbarossa in 1941. Germany and the USSR launched a joint war against Poland in September of 1939, which the Soviets followed up with invasions of Finland, Romania, and the Baltic states across the following year. For the campaign against the Soviet Union, the Germans allotted almost 150 divisions containing a total of about 3,000,000 men. The war between Germany and the Soviet Union officially began in late June 1941, although the threat of conflict had loomed since the early 1930s.