Kim Il-sung (pronounced [kim ilsʰʌŋ]; born Kim Sŏng-ju; 15 April 1912 – 8 July 1994) was the leader of the Democratic People's Republic of Korea, commonly referred to as North Korea, from its establishment in 1948 until his death in 1994. He held the posts of Prime Minister from 1948 to 1972 and President from 1972 to his death. He was also the leader of the Workers' Party of Korea from 1949 to 1994 (titled as chairman from 1949 to 1966 and as general secretary after 1966). He invaded South Korea in 1950, and almost succeeded in overrunning the entire peninsula if not for UN intervention. The Korean War, sometimes referred to as the Korean Civil War, was stopped with a cease-fire signed on 27 July 1953. As of now, the Korean War has technically not ended.His tenure as leader of North Korea has often been described as autocratic, and he established an all-pervasive cult of personality. From the mid-1960s, he promoted his self-developed Juche variant of socialist organisation, which later replaced Marxism-Leninism as the ideology of the state. In the U.S. Library of Congress Country Study on North Korea in 2009, he was described as "one of the most intriguing figures of the twentieth century". He was in power during the terms of office of six South Korean presidents, seven Soviet leaders, ten U.S. presidents, ten UK Prime Ministers, twenty-one Japanese prime ministers, five popes of the Roman Catholic Church and coincided with the entire apartheid era of South Africa.His son Kim Jong-il became his formal successor at the 6th WPK Congress, and he succeeded him in 1994. The North Korean government refers to Kim Il-sung as "The Great Leader" (위대한 수령, widaehan suryŏng) and he is designated in the North Korean constitution as the country's "Eternal President". His birthday is a public holiday in North Korea and is called the "Day of the Sun".