Peter I of Yugoslavia was the king of the Kingdom of Serbs, Croats, and Slovenes, later known as Yugoslavia, from 1918 until his death in 1921. Born on June 11, 1844, he was a member of the House of Karađorđević and played a significant role in the establishment of the new kingdom after World War I. His reign was marked by efforts to unify the diverse ethnic groups within the country. Peter I was known for his democratic ideals and commitment to social reforms. He sought to improve the lives of his subjects and promote national unity. His popularity grew due to his humble demeanor and dedication to the people, earning him the nickname "the People's King." He passed away on August 16, 1921, leaving a legacy of hope for a united Yugoslavia.