Task: Question Generation
Input (English): Dreyfus writes that after the Phagmodrupa lost its centralizing power over Tibet in 1434, several attempts by other families to establish hegemonies failed over the next two centuries until 1642 with the 5th Dalai Lama's effective hegemony over Tibet.
Output (English): What year did the 5th Dalai lama start to dominate over Tibet?