Alexander I also called Alexander I Karadordevic or Alexander the Unifier (Serbian, Croatian, Serbo-Croatian: Aleksandar I Karadordevic) (Cetinje, Principality of Montenegro, (16 December 1888 [O.S. 4 December] – Marseille, France, 9 October 1934) of the Royal House of Karadordevic (Karageorgevich) was the first king of the Kingdom of Yugoslavia (1929–34) and before that king of the Kingdom of Serbs, Croats and Slovenes (1921–29).