In 1924, after the Bogd Khaan died of laryngeal cancer or, as some sources claim, at the hands of Russian spies, the country's political system was changed. The Mongolian People's Republic was established. In 1928, Khorloogiin Choibalsan rose to power. The early leaders of the Mongolian People's Republic (1921–1952) included many with Pan-Mongolist ideals. However, changing global politics and increased Soviet pressure led to the decline of Pan-Mongol aspirations in the following period.