One of the three temples of the Korean Triratna ("three jewels": Buddha, dharma, sangha). Thondosa is dedicated directly to the Buddha (while the sangha, the monastic community, is dedicated to Songwansa temple, and the dharma, the teachings of the Buddha, is dedicated to Haeinsa).
The temple was founded in 646 by the master Chazhang, who visited China and brought from there such relics as the robe of the Buddha, an alms bowl, and part of the bones of the Buddha's skull. These relics were divided among three temples, Thondosa is the only one preserved. Due to the fact that the "true relics" of the Buddha are in a mortar at the top of the "diamond stairs", there is no statue of Buddha in the main building of the temple dedicated to Shakyamuni Buddha - for why create an image of someone who is in the form of relics directly in the temple?
There are several versions of the origin of the name of the temple. Thon means "to pass/to be like"; do - improve, go to nirvana, follow the rules of Buddhist life. Lay people aspiring to become monks had to "walk the diamond ladder." The second version: "acquire absolute knowledge, lead all beings to nirvana" - the mission of the branch of Mahayana Buddhism. The third version: the mountain at the foot of which the temple is located resembles the Eagle Mountain (Gridhrakuta), where the Buddha preached (and the name of the mountain sounds the same in Korean: Yongchhuksan / Yeonchisan - "Eagle Mountain").
The temple was heavily built during the Imjin War of 1592-1598, but was rebuilt by 1645. By the number of buildings and structures - more than 50 - it is considered the largest in Korea.