The Treasury of Lives defines royalty as members of families that controlled empires and kingdoms as well as principalities, and specifically as individuals who are identified by titles such as king, queen, prince and so forth. The Pugyel dynasty, also known as the Tibetan Yarlung dynasty, was the imperial royal family that ruled Tibet from the 7th to 9th centuries. After the break-up of the empire, descendants of the Pugyel kings ruled in Guge, western Tibet. For a period of three hundred years until the Ganden Podrang government was established in 1642, the Pakmodru, Rinpung and Tsang hegemonies ruled central Tibet. Outside of the central Tibetan region, there were royal houses that ruled over separate kingdoms. In Amdo, the house of Tsongkha ruled an extremely powerful kingdom, and the house of Gatsang ruled the Chone kingdom. In Kham, there were the kingdoms or principalities of Derge, Nangchen, Chakla and Lingtsang, whose kings balanced relations with both Beijing and Lhasa. Some of these royal houses trace their ancestry back to the early Pugyel period, such as the House of Derge, which traces its ancestry to Gar Tongsten, the renowned minister of the Pugyel kings. The House of Ling claims descent from the legendary King Gesar of Ling. Elsewhere in the Himalayan region were the neighboring kingdoms of Mustang (later subsumed into Nepal), Sikkim and Ladakh (later subsumed into India), and Bhutan. The Kings of Mustang claim divine descent from a celestial ancestor named Ode Gunggyel. The Namgyel dynasty of Sikkim traced its origins to the Ao Dong clan, which probably came from the northeast of Tibet. The Bhutanese dynasty of the Wangchuck house was established in 1907 by an assembly that elected Ugyen Wangchuck to be the first King of Bhutan.