Tsongkhapa is traditionally regarded as the founder of the Tibetan Buddhist school called Gelug.
Tsongkhapa, whose full Tibetan name is Je Tsongkhapa Lobzang Drakpa, was a major Tibetan scholar and religious reformer who lived from 1357 to 1419. He emphasized rigorous study, monastic discipline, philosophical reasoning, and systematic tantric practice.
The Gelug tradition grew from his teachings and institutions. Tsongkhapa founded Ganden Monastery in 1409, and the tradition is therefore sometimes called the Ganden school. The Dalai Lamas later became its most internationally recognized leaders, although the Gelug tradition is broader than the institution of the Dalai Lama.
Tsongkhapa is not the same figure as Padmasambhava, who is traditionally associated with the early transmission of Buddhism to Tibet and the Nyingma school. Milarepa is celebrated as a yogi and poet, while Atisha was an earlier Indian teacher who influenced Tibetan Buddhism.