Foremost among ancient heroes were Fan Shihman, greatest ruler of the Funan Empire (150–550), and Jayavarman II and Jayavarman VII, monarchs of the Khmer Empire who ruled between the 10th and 13th centuries. Prince Norodom Sihanouk (b.1922), who resigned the kingship and won Kampuchea's independence from France, is the best-known living Cambodian. In exile in China during 1970–75, he founded the GRUNK government, from which he resigned in April 1976. In July 1982, he became president of the CGDK. Khieu Samphan (b.1931), a former Marxist publisher and leader of the insurgency in Kampuchea, was named chairman of the State Presidium in the GRUNK government in April 1976, replacing Sihanouk as chief of state. The de facto head of the GRUNK regime during 1975–79 was Pol Pot, the nom de guerre of Saloth Sar (1925–98), who presided over the drastic restructuring of Kampuchean society that left as many as 2–3 million dead in its wake. Heng Samrin (b.1934) became president of the Council of State of the PRK in 1979. Photographer Dith Pran (b. 1943), whose ordeal with the Khmer Rouge was portrayed in the film The Killing Fields , helped chronicle the atrocities of the Pol Pot regime.