Mongolia was the center of the Mongol Empire in the thirteenth century and was later ruled by the Qing Dynasty from the end of the seventeenth century until 1911, when an independent government was formed with Russian assistance. The Mongolian People's Republic was proclaimed in 1924, leading to the adoption of communist policies and a close alignment to the Soviet Union. After the fall of communism in Mongolia in 1990, Mongolia adopted a new constitution which was ratified in 1992. This officially marked the transition of Mongolia to a multi-party political system. Mongolia's political system is parliamentary republic.