His growing influence angered not only his Tibetan enemies, but also several powerful rival Buddhist schools of western Bhutan such as the Lhapa sect. Eventually, the Tsangpa invaded Bhutan in collaboration with the Lhapa hierarchs in order to eliminate Ngawang Namgyal in 1619. This first invasion was eventually defeated by the Bhutanese chieftains who had rallied to Zhabdrung's support, but the conflict between him and the Tsangpa continued, especially since a smallpox epidemic that killed King Karma Phuntsok Namgyal and many other members of the Tibetan dynasty was attributed to Ngawang Namgyal's alleged magical powers.