In the aftermath of the Russian Revolution, Persia had become a battleground. In 1917, Britain used Iran as the springboard for the launching of an expedition into Russia as part of their intervention in the Russian Civil War on the side of the White movement. The Soviet Union responded by annexing portions of northern Persia, creating the Persian Socialist Soviet Republic. The Soviets extracted ever more humiliating concessions from the Qajar government, whose ministers Ahmad Shah was often unable to control. By 1920, the government had lost virtually all power outside its capital: British and Soviet forces exercised control over most of the Iranian mainland.