On 10 October 1914, Ferdinand's uncle,
Carol I, died without surviving issue. Ferdinand succeeded him as King of Romania, reigning until his own death on 20 July 1927.
World War I Though a member of a cadet branch of
Germany's ruling
Hohenzollern imperial family, Ferdinand presided over his country's entry into
World War I on the side of the
Triple Entente against the
Central Powers, on 27 August 1916. Thus he gained the sobriquet "the Loyal", having kept the oath he swore before the
Parliament of Romania in 1914: "I will reign as a good Romanian." poster) As a consequence of this "betrayal" of his German origin,
German Emperor Wilhelm II had Ferdinand's name erased from the Hohenzollern House register. Despite the setbacks after the entry into war, when
Dobruja and
Wallachia were occupied by the Central Powers, Romania fought in 1917 and stopped the German advance into
Moldavia. When the new
Bolshevik government of Russia
sued for peace in 1918, Romania was surrounded by the Central Powers and forced to conclude
a peace treaty of its own; however, Ferdinand refused to sign and ratify the Treaty of Bucharest. Allied forces then advanced on the
Thessaloniki front and they knocked Bulgaria out of the war. Ferdinand ordered the re-mobilization of the
Romanian Army, and Romania re-entered the war on the side of the Triple Entente.
After the war The outcome of Romania's war effort was the union of
Bessarabia,
Bukovina, and
Transylvania with the
Kingdom of Romania in 1918. Ferdinand became the ruler of a greatly enlarged Romanian state in 1918–1920 following the victory of the Entente over the Central Powers, a
war between the
Kingdom of Romania and the new
Hungarian Soviet Republic, and the
Russian Civil War. He was crowned king of "Greater Romania" in a spectacular ceremony on 15 October 1922 in the courtyard of the newly consecrated "
Coronation Cathedral" in the historic princely seat of
Alba Iulia in Transylvania. A new period of Romanian history began on the day of the
Union of Transylvania with Romania (
Great Union Day,
Marea Unire). This period would come to an end with international treaties, in the years leading to World War II, which ceded parts of Romania to its neighbors. As such, they are widely seen as an attempt to provoke the country into taking sides and joining the war. Domestic political life during his reign was dominated by the conservative
National Liberal Party, which was led by the brothers
Ion and
Vintilă Brătianu. The acquisition of Transylvania had the unintended effect of enlarging the electoral base of the opposition, whose principal parties united in January 1925 – October 1926 to form the National Peasant Party. ==Death==