Secret protocols of the Molotov–Ribbentrop Pact, adjusted by the German-Soviet Frontier Treaty, divided Eastern Europe into Soviet and Nazi spheres of influence. The three Baltic states fell to the Soviet sphere. During the subsequent invasion of Poland, the Red Army captured Vilnius, regarded by Lithuanians as their capital. According to the Soviet–Lithuanian Mutual Assistance Pact of 10 October 1939, Soviet Union transferred Vilnius and surrounding territory to Lithuania in exchange for the stationing of 20,000 Soviet troops within the country. It was a virtual sacrifice of independence, as reflected in a known slogan "Vilnius – mūsų, Lietuva – rusų" (Vilnius is ours, but Lithuania is Russia's). Similar Mutual Assistance Pacts were signed with Latvia and Estonia. When Finland refused to sign its pact, the Winter War broke out.