In 1645 the newly installed Dalai Lama commissioned a palace on Lhasa's Red Hill, the site of a ruined seventh century fortress associated with the ancient Tibetan emperor Songtsen Gampo, and construction of what became the Potala Palace, part fortress, part monastery, part seat of government, continued in stages for decades, with much of the iconic Red Palace section completed only after his death and its completion concealed from the public for years by his regent, Desi Sangye Gyatso, to avoid destabilizing the new state during a politically fragile transition.
Beyond statecraft, the Fifth Dalai Lama was also a serious tantric practitioner and prolific author in his own right, notably drawn to Nyingma, the oldest of the Tibetan Buddhist schools, in tension with his own Gelug institutional position, and he worked deliberately to reconcile and patronize multiple Tibetan Buddhist schools rather than favoring the Gelug alone, a policy that helped stabilize a state built on the ashes of recent sectarian war. His unusually long and eventful reign, and the scale of the Ganden Phodrang state he built, is why Tibetan tradition remembers him simply as the Great Fifth, a title carried by none of the other thirteen Dalai Lamas before or since, and why his life supplies the clearest case of full temporal rulership actually exercised by a Dalai Lama in Tibetan history.