Ferdinand I of Romania (Alexander the Liberator)

Ferdinand I (Ferdinand Viktor Albert Meinrad; 24 August 1865 – 20 July 1927), nicknamed Întregitorul ("the Unifier"), was King of Romania from 10 October 1914 until his death in 1927. Ferdinand ruled the Balkan nation during the Transylvanian War, which saw the Romanians conquer Transylvania from the Hungarian People's Republic (hence forth the nickname).

Ferdinand was the son of Leopold, Prince of Hohenzollern-Sigmaringen, and Infanta Antónia of Portugal, daughter of Queen Maria II of Portugal and Prince Ferdinand of Saxe-Coburg and Gotha, heir to the Slovakian-originated Hungarian magnates of Kohary on his mother's side. Ferdinand became crown prince of Romania in 1889 when he was adopted by his paternal uncle, King Carol I, whose only child had died in 1874.

In 1918, four years after becoming King of Romania, the Habsburg Empire collapsed after their defeat in the First World War. A Marxist-Leninist government was established in Hungary in the midst of the political and social chaos. Ferdinand met with his government and decided to declare war. The motive was the nationalist belief that Transylvania is rightful Romanian territory, as well as the fear of the spread of Marxism if the revolutionaries in Hungary were successful.

The Romanian Army marched into Transylvania swiftly, with little resistance due to instability in Hungary. By the end of the year, Romania annexed Transylvania and Hungary fell into a two year civil war. Ferdinand died from cancer in Sinaia in 1927, and was succeeded by his son, Carol II.