Buddhist tradition holds that the cremation of the Buddha left, among other relics, two teeth; one is said to have gone to Sri Lanka, where it is enshrined at Kandy, and the other to have travelled north and east into Central Asia and China. The tooth at Lingguang is identified with this second relic, brought, by the temple's account, from the region of Udyana through Khotan into China in the fifth century and eventually to the hills west of Beijing.
Whatever the details of that long transmission, the tooth became one of the most venerated relics in Chinese Buddhism, its authority resting less on forensic proof than on an unbroken chain of enshrinement, imperial patronage and pilgrimage. The distinction it shares with Kandy, that of being one of only two recognised tooth relics, gives it a special place in the modern Buddhist world and helps explain why the Chinese state has treated it as a diplomatic asset, lending it for veneration to Buddhist-majority countries across Asia.