In between 14th century and 15th century when the Reformation movement started to change the European religious society, there was also a Buddhism reformation in Tibet initiated by Tsongkhapa, the teacher of Panchen and Dalai.
Tsongkhapa (1357-1419, when the inland China was the Ming Dynasty) is a religious reformist, social activist, and the founder of the Gelug Sect Tibetan Buddhism.
In 1388, Tsongkhapa showed his determination to reform the contemporary Tibetan Buddhism by stressing the importance of abiding by religious commandments during Buddhist cultivation. He demanded his followers to wear yellow hats to cast off the bad habits of defying and violating the Buddhist commandments, which was popular among the red and black hats followers of other sects. That marked the founding of a new Tibetan Buddhism school, the Gelug Sect (or Yellow Hat Sect).
Tsongkhapa has eight famous disciples: Gyeltsab Je (the principal disciple, 1364-1431), Khedrup Je(the second disciple, 1385-1438), Drakpa Gyeltsen (1374-1432), Jamyang Tashi Pelden (founder of the Drepung Monastery), Shakya Yeshe (founder of the Sera Monastery), Jampel Gyatso, Sherab Sengge, and Gendun Drup (the founder of Tashilhunpo Monastery, 1391-1474).
Among the eight disciples, two of them are later granted the Dalai Lama and Panchen Lama, formulating two hereditary systems of Tibetan Buddism. Khedrup Je is the first Panchen Lama and Gendun drup is the first Dalai Lama.
Born of a eupatrid in Tsongkha area in Qianghai Province where the contemporary Kumbum Monastery located, Tsongkhapa was the fourth children among his six siblings of his parents.
He undertook to obey the five commandments at the age of three. It is said that he was so talented and smart to apprehend reading, reciting and writing that he was able to be ordained as a monk of the Kadam school of Tibetan Buddhism only one year after. In the following ten years, he studied Tibetan languages and theories of Esoteric and Exoteric Tibetan Buddhism.
At 16 years old (1372 AD), Tsongkhapa went to Tibet with his uncles and other believers to cultivate Tibetan Buddhism. At that time, Tibet had many religious sects including Kadam, Nyingma, Kagyu, Sakya, and Bon who held almost equal positions in different regions. He then went to each place for the knowledge from various accomplished lamas.
During the next nearly 15 years, Tsongkhapa became famous owing to his outstanding achievements in each subject of tantric and exoteric Tibetan Buddhism. Moreover, he also consolidated great theory books of exoteric Tibetan Buddhism and sorted out the five major Shatras, which are the present major subjects that Tibetan Buddhists cultivate for at least ten years to apprehend the Exoteric Tibetan Buddhism.
In 1408, Emperor Yongle (1360-1424), the third emperor of the Ming Dynasty (1368-1644 A.D.) sent his envoy to Tibet asking Tsongkhapa to preach Tibetan Buddhism in the inland. Busy preparing for the grand religious assembly in Jokhang Temple the next year, Tsongkhapa declined the emperor's invitation and sent his excellent disciple Shakya Yeshe as his representative to pay homage to the emperor. Emperor Yongle conferred him a honorific title as "State Preceptor Bodhisattva in the Western Heaven".
Tsongkhapa passed away on October 25 in 1419 at the age of 63. The next year, people built a stupa in Ganden Monastery in Lhasa and buried him there. From then on October 25 in the Tibetan calendar became a religious festival in honor of Tsongkhapa, which is nowadays "Butter-lamp Festival".
From then on, the Gelug Sect of Tibet Buddhism, or the Yellow Hat Sect, gained full-wing through historical development in Tibet.