Mongolia borders Russia to the north and the People's Republic of China to the south, east, and west. The Mongol Empire was founded by Genghis Khan in the 13th century. It eventually submitted to the Manchu rulers of Qing China in the 17th century. After the Soviet-backed revolution of 1921 it became a one-party state known from 1924 as the Mongolian People's Republic. Following the democratic revolution of 1990, which ushered in multiparty politics and a market economy, the new constitution adopted in 1992 renamed the country Mongolia. The third edition of the Historical Dictionary of Mongolia greatly expands on the previous edition through a chronology, an introductory essay, a bibliography, appendixes, and over 1000 cross-referenced dictionary entries on important people, places, events, and institutions, as well as significant political, economic, social, and cultural aspects.