The three oldest biographies of Tsangpa Gyare, the Founder of the Drukpa Kagyu School
Among the four prominent Tibetan Buddhist schools, the Kagyü (Bka’ brgyud) school produced the most numbers of sub-schools such as Karma Kagyü (Karma bka’ brgyud), Drikung Kagyü (’Bri gung bka’ brgyud) and Drukpa Kagyü (’Brug pa bka’ brgyud). The latter spread in surrounding regions and became a state religion in Bhutan.