Yun Poson
After Rhee's government was ousted by a student-led pro-democracy uprising, Yun was elected president on August 13, 1960. He was merely a figurehead, as South Korea had switched to a parliamentary system in response to the authoritarian excesses of Rhee's regime.  After Park Chung Hee's coup in 1961, he stayed on briefly to provide legitimacy to the regime, but resigned on March 22, 1962. He opposed Park's authoritarian rule and ran for president twice in 1963 and 1967, losing each time. After receiving suspended sentences several times for anti-government activities, Yun retired from politics in 1980 and focused primarily on cultural activities until his death from diabetes and high blood pressure. He died in 1990.