Peter I of Serbia

Peter was born the third son of a deposed Serbian prince and spent his early decades in exile, fighting with the French Foreign Legion in the Franco-Prussian War and joining the Herzegovina uprising against the Ottomans under the alias Peter Mrkonjić. He married Princess Zorka of Montenegro in 1883 and became head of the Karađorđević dynasty after his father's death in 1885. When King Alexander I Obrenović was murdered in the May Coup of 1903, Peter ascended to the Serbian throne and governed with a constitutional hand - his reign known for press freedom, political liberties, and what some called a "golden age." He commanded the Royal Serbian Army through the Balkan Wars, then in 1914, as age caught him, handed regency to his son Alexander. World War I forced the old king and his army into a punishing retreat across Albania. He died in 1921 at seventy-seven, three years after becoming the first king of the Serbs, Croats and Slovenes.