The Non-Aggression Pact, also known as the Molotov–Ribbentrop Pact was signed in Moscow on August 24, 1939. It was an agreement between Nazi Germany and the Soviet Union not to attack each other. The pact remained in effect until June 22, 1941 when Germany implemented Operation Barbarossa, invading the Soviet Union. The treaty included a secret protocol dividing Northern and Eastern Europe into German and Soviet spheres of influence.