How did Tibetan Buddhism become widespread among Mongols?

While Tibetan Buddhism had been present among the Mongol aristocracy as early as the reign of Kublai Khan, it did not gain widespread popular support during that period. The religion became deeply integrated into Mongol society primarily through the efforts of Altan Khan in the late 16th century.12

In 1578, Altan Khan met with the high lama of the Dge-lugs-pa (Yellow Hat) school, leading to his conversion and the adoption of the sect as the official religion under his rule. This alliance restored a patron-priest relationship, with Altan Khan conferring the title Dalai Lama upon the sect's leader.321

Beyond religious devotion, Mongol leaders saw the Tibetan monastic system as a way to develop a literate class for bureaucracy without the risk of being assimilated into Chinese society. This transition was further solidified by the translation of numerous scriptures into the Mongolian language and the later establishment of the Javzandamba line of spiritual rulers, which deeply embedded Tibetan Buddhism into the cultural and political fabric of Mongolia.142