Longmen is a museum of Chinese Buddhist sculpture, and also a rare written record of the economy of devotion that produced it.
Two dynasties in stone. Carving began around 493, when the Northern Wei moved their capital to Luoyang, and continued through the Tang. The two phases look different (the elongated, spiritualised Wei figures against the fuller, more naturalistic Tang ones), so the cliffs read as a timeline of taste as well as of faith. The summit of it is the Fengxian temple's Vairocana Buddha, about seventeen metres high, completed around 675; the empress Wu Zetian is named among its donors, and tradition holds its face was modelled on hers.
The inscriptions. What makes Longmen unusual is that thousands of the niches carry dedicatory inscriptions naming the donor, the date and the wish, for a dead parent's rebirth, for the emperor's long life, for a lay society's collective merit. The site is therefore not only art but data: it tells you who commissioned Buddhist merit, when, and to what end, across two dynasties.
The looting. Much has been lost. In the early twentieth century heads and whole reliefs were cut from the walls and sold to Western collectors; the celebrated relief of an imperial procession was removed and is now divided between American museums. Some pieces have returned; many have not. UNESCO inscribed the grottoes in 2000.