Gia Long dug up the Tây Sơn emperors in 1802, pounded their bones and locked their skulls in a prison

The Tây Sơn brothers overthrew the Nguyễn lords and the Lê emperors. The second brother, Nguyễn Huệ, ruled as Emperor Quang Trung and drove out a Qing army in 1789. The Nguyễn court's official biographies, the Đại Nam chính biên liệt truyện, record that he sent a stand-in, Phạm Công Trị, to the Qing court under his own name. Huệ died in autumn 1792, aged about 40, and was buried south of the Perfume River. His court told the Qing emperor that Huệ's will asked for burial at West Lake in Hanoi, and the emperor sent an elegy. His young son, Quang Toản, succeeded. Nguyễn Ánh, heir of the Nguyễn lords, whose family tombs the Tây Sơn are said to have desecrated^†, fought on. In June 1802 villagers caught Quang Toản fleeing north. That winter Nguyễn Ánh, now Emperor Gia Long, presented the captives at his ancestral temple and executed them, by five elephants according to Wikipedia's reading of the Đại Nam thực lục^†. The biographies say he broke open the tombs of Nguyễn Nhạc and Nguyễn Huệ, pounded and threw away the bones, and kept their heads locked in a prison room. In 1831 the court caught Nhạc's two surviving sons and a grandson and had them cut in half at the waist. The record ends: no Tây Sơn kin remained. In 2007 a Huế researcher placed Quang Trung's tomb in the hills south of the old capital, but no excavation has confirmed it.