Lithuania becomes the first Soviet republic to proclaim its independence from the USSR. During the medieval period, Lithuania was one of the largest states in Europe, stretching from the Baltic to the Black Sea. In 1795, Lithuania was absorbed into Russia. It briefly regained independence between the world wars but in 1944 was incorporated into the USSR. Soviet leader Mikhail Gorbachev's liberalization of Soviet society in the 1980s led Lithuania to reassert its identity, and in 1990 formal independence was proclaimed. Moscow sent troops to occupy Vilnius, the Lithuanian capital, but on September 6, 1991, agreed to grant independence as the Soviet Union crumbled.