Ismail I
Following his conquest of Iran and Azerbaijan, Ismail I made conversion mandatory for the largely Sunni population. The Sunni Ulema or clergy were either killed or exiled. Ismail I, brought in mainstream Twelver Shi'a religious leaders and granted them land and money in return for loyalty. Later, during the Safavid and especially Qajar period, the Shiʻi Ulema's power increased and they were able to exercise a role, independent of or compatible with the government.