Peter I (1844-1921) became Serbia’s first constitutional monarch in 1903, following the assassination of King Alexander Obrenović. As monarch, Peter’s aggressive policies led to the expansion of Serbian territory through the Balkan Wars of 1912 and 1913. In 1914, Peter, who was in poor health, gave control of the government to his son Alexander, who served as regent (temporary ruler). During World War I (1914-1918), a combined invasion by Austria-Hungary, Bulgaria, and Germany forced Peter and the Serbian army to retreat into exile on the Greek island of Corfu. In 1918, at the conclusion of the war, the Kingdom of the Serbs, Croats, and Slovenes (later renamed Yugoslavia) was formed. Peter became its first king.
Peter Karadjordjević was born in Belgrade on July 11, 1844. His name is also spelled Petar. He spent most of his early life in exile in France and Switzerland. He died on Aug. 16, 1921. His son Alexander I succeeded him as king.
See also Alexander I ; Serbia (History) .