How did Tibetan Buddhism become widespread in Mongolia during the 15th and 16th centuries?

The spread of Tibetan Buddhism in Mongolia during the 15th and 16th centuries was driven by both political and social motivations. Mongol princes sought to establish a literate class to serve as a bureaucracy without relying on the Chinese language, which carried the risk of cultural assimilation. The Tibetan monastic system provided a ready-made structure of clerical bureaucrats who were not strong enough to politically dominate Mongolia.12

A pivotal moment occurred in 1578 when Altan Khan met with the leader of the Dge-lugs-pa (Yellow Hat) school. Altan converted to this sect, and they restored a traditional patron-priest relationship by declaring each other incarnations of historical figures. Altan conferred the title Dalai Lama upon the leader, Sonam Gyatso, establishing the sect as the official religion under his rule. This revival was further supported by a significant effort to translate religious scriptures into the Mongol language, cementing the faith's influence across the region.123