Ngawang Lobsang Gyatso was born in 1617 in the Yarlung valley to a family claiming descent from Tibet's old imperial line, and he came of age during a period when Tibet was fractured among competing regional rulers and rival Buddhist schools, most sharply the Gelug school his own Dalai Lama lineage belonged to against the Karma Kagyu school backed by the ruling king of Tsang.
The conflict was resolved not by the Dalai Lama's own forces, which were negligible, but by Gushri Khan, chief of the Qoshot Mongols, who invaded Tibet on the Gelug school's behalf, defeated the King of Tsang and the school's other rivals by 1642, and then formally handed political authority over the whole of Tibet to the twenty-five year old Dalai Lama rather than ruling directly himself, installing him as head of state at Shigatse's Samdrubtse Palace. This arrangement, spiritual authority now backed and enforced by Mongol military power, created the Ganden Phodrang, Tibet's first unified centralized government since the collapse of the old imperial dynasty many centuries earlier, and set the pattern, spiritual head of state legitimated and protected by an outside patron power, that would recur across Tibetan history down to the twentieth century, including in different form under Chinese Qing dynasty oversight.