 The Uyghur Khaganate to the north collapsed due to a revolt by the Yenisei Kirghiz in year 840 and many displaced people fled to Tibet.According to one source, he only reigned for a year and a half, while others give six or thirteen years.According to traditional accounts, a Buddhist hermit or monk named Lhalung Pelgyi Dorje assassinated Langdarma in 842 or 846.