Gavrilo Princip was a Bosnian Serb student who assassinated Archduke Franz Ferdinand of Austria and his wife Sophie, Duchess of Hohenberg. This South Slav nationalist was responsible for starting World War I with his act of assassinations on June 28, 1914. He was only 19 when he killed the heir to the Austrian throne. The entire world went into conflict which would eventually cost the lives of 15 millions people. World War I availed to bring on the collapse of the four East European imperia (Austro-Hungarian, German, Russian, and Ottoman), and the establishment of a number of incipient nation-states, including the Kingdom of Serbs, Croats, and Slovenes. There, Princip was hailed as a national hero who had coalesced the South Slavs and liberated them from peregrine rule.