Dalai Lama (UK: , US: ; Tibetan: ཏཱ་ལའི་བླ་མ་, Wylie: Tā la'i bla ma [táːlɛː láma]) is a title given by Altan Khan, the first Shunyi King of Ming China. He offered it in appreciation to the leader of the Gelug school of Tibetan Buddhism, Sonam Gyatso, who received it in 1578 at Yanghua Monastery. At that time, Sonam Gyatso had just given teachings to the Khan, and so the title of Dalai Lama was also given to the entire tulku lineage.
https://en.wikipedia.org/wiki/Dalai_Lama