The Drepung monastery is one of the three Gelukpa university monasteries of Tibet (the other two being Ganden and Sera). Drepung is the largest of all Tibetan monasteries and at its peak also was the largest monastery in the world, housing 15000 monks in 1959. Founded in 1416 by Jamyang Chojey, the founder of the Gelukpa school, it is located on the Gambo Utse mountain, 5 km west of Lhasa.