In 1700, Mongol ruler Lhazang Khan assumed power over Tibet, initially ruling jointly with Desi Sanggye Gyatso. After the Sixth Dalai Lama’s death in 1706, the Seventh Dalai Lama was recognized in secret, spending the early years of his life outside of central Tibet, until the reign of Lhazang Khan ended in 1717 when the Dzungar Mongols invaded Tibet. In 1720, Tibetan and Manchu armies forced out the Dzungars and the Seventh Dalai Lama was installed in the Potala. Despite rebellions among Tibetans and Mongols in eastern Tibet in the 1720s, Manchu authority was maintained, and most of Amdo was formally annexed by the Qing under the name of Qinghai Province. Beginning in 1727, official Manchu representatives, the Amban, were stationed in Lhasa. In that same year, Polhane's rule began, supported by the Manchu court. Pelpung Monastery was established in 1727 by the Eighth Tai Situ, Chokyi Jungne. The Derge printing house was established in 1729 and its editions of the Kangyur and Tengyur were printed in 1733 and 1744, respectively. In 1750, Polhane’s son Gyurme Namgyel died during a failed rebellion and the Seventh Dalai Lama succeeded him to rule Tibet as head of state. In 1758, the Eighth Dalai Lama was born. The Golden Urn Decree of Qianlong in 1792 attempted to mandate Manchu approval of high-level tulku recognition. The Tibetan and Qing armies jointly crushed the independent Bon kingdoms of Gyelrong, converting the Bon monasteries to the Geluk tradition. After decades of expansion around the Himalayas, the Nepalese invaded Tibet in 1792, and were driven back by Manchu forces.