The Soviet Union's invasion of Afghanistan began the day before Christmas in 1979. The initial deployment, under the directive and leadership of Soviet leader Leonid Brezhnev started a nine-year long war. The Soviets were there to support the Marxist government of the Democratic Republic of Afghanistan and help them in their fight against the Afghan Mujahideen guerrilla movement. The Mujahideen guerrilla movement received unofficial military and financial support from other countries, including the United States to counteract the Soviet influence. The Afghan government itself received aid from India due to its status as an ally of the Soviet Union.
As the Soviet occupation dragged on year after year, the conflict in Afghanistan was often referred to as the "Soviet Union's own Vietnam War or, sometimes "the Bear Trap.".
Russian military involvement in Afghanistan was hardly novel. Russia and Afghanistan have had a long history, going all the way back to Tsarist expansions in the popularly-known "Great Game" that existed between Russian and Britain. Russian forces seized Afghan territory as early as 1885 and their interest in the region continued throughout the Soviet era. In fact, Russia sent billions of dollars in economic and military aid to Afghanistan between 1955 and 1978, when they began to occupy the country.
Upheaval in the region became intensified when the Islamic Revolution took place in neighboring Iran. The Afghan police, assisted by the Soviets, kidnapped and killed the United States Ambassador to Afghanistan, resulting in a major degradation in Afghanistan and United States relations. The affair also prompted the United States to deploy twenty ships to the Persian Gulf and the Arabian Sea. They also deployed two aircraft carriers, which facilitated a constant stream of warfare threats between the United States and Iran.
The final Soviet troop withdrawal troop started on May 15, 1988, and ended on February 15, 1989 under the direction of the last Soviet leader, Mikhail Gorbachev.