Drepung Monastery is considered one of the "Three Great Monasteries" of Tibetan Buddhism, along with the Ganden Monastery and the Sera Monastery. Situated at the foot of the Mt Gambo Utse, 5km (3.1 miles) west of central Lhasa, it was once the largest monastery in the world, holding almost 10,000 monks. It was established in 1416 by Jamyang Choje, a disciple of Tsongkhapa, and before the building of the Potala Palace it was the seat of the Dalai Lamas. This gave the monastery great political importance in Tibet, an importance that remained after the Dalai Lamas ceased to reside there.
The main buildings of the monastery, centered on two white pagodas, are the Ganden Potrang, the Coqen Hall, the four Zhacangs (tantric colleges) and the Kamcuns. The Ganden Potrang originally served as the residence of the Dalai Lamas. The huge Coqen Hall lies at the heart of the monastery, and is large enough for 7,700 monks to recite sutras at the same time, which makes it the largest of its kind in the Tibetan areas in China. It also houses a number of precious objects, including statues of the Buddha, rare sutras and a Gangyur Tripitaka written in gold powder.
Several flagstoned courtyards in the grounds of the monastery are the scene of lively religious debates of the kind seen at Sera Monastery. One of the most important events associated with Drepung Monastery occurs at the beginning of the annual Shoton Festival around mid-August. The festival marks the end of a month-long retreat by monks, during which time they have not been able to go outside the monastery buildings. At Drepung, the Shoton Festival period opens with the unfurling of a giant thangka image of the Buddha on the hillside near the monastery, accompanied by the sound of bugles and the burning of incense. Thousands of worshippers gather to try to touch the thanka before it is rolled up and put away.