From 1691, Outer Mongolia had been a territory of the Chinese Qing dynasty. A move for independence had been stoked at the start of the 20th century after the Qing dynasty implemented cultural assimilation policies in Outer Mongolia to strengthen the Chinese identity of the territory.
When the Qing dynasty collapsed in 1911, Mongolia declared independence. The newly formed Republic of China considered Outer Mongolia to be part of its territory; and emboldened by the collapse of the Russian Empire, Chinese troops were sent to occupy Mongolia.
The Chinese were ousted in February 1921, when the Mongols received support from Russian soldiers fighting against the Bolsheviks.
This forced the hands of the Soviet Russians who supported the Mongolian People’s Party and on July 11th 1921, Mongolia again declared independence, starting a close relationship with the Soviet Union that would last until 1990.
On November 26th 1924, the Mongolian People’s Republic was proclaimed and Mongolia became the world’s second communist country.
November 26th was made a public holiday on November 18th 2016 in accordance with the parliamentary resolution.
On becoming a republic, the capital of Mongolia, Niislel Khüree was renamed Ulaanbaatar (Ulan Bator), meaning “Red Hero.”