Ferdinand was King of Romania from 1914 to 1927. He was originally from Germany but became the heir to the Romanian throne when he converted from Catholicism to Orthodoxy. During World War I, Ferdinand rejected his German heritage and allied Romania with the Triple Entente against the Central Powers, including neighboring Bulgaria led by his cousin Tsar Ferdinand I. Through Ferdinand's leadership and Romania's efforts in the war, Bessarabia, Bukovina, and Transylvania were united with Romania in 1918, consolidating the modern Romanian state.

1. Ferdinand the 1st/ “The
Unifier”.
• Ferdinand was King of Romania from 1914 until 1927.
He was born in Germany with the name of
Hohenzollern-Sigmaringen, the name being changed
later just to Hohenzolleren, he was the son of Leopold
and Antonia of Portugal. Young Ferdinand became the
heir of his childless uncle, Carol the 1st of Romania, and
so he’d become king, not until he swaped from
catcholicism to orthodoxy. Ferdinand’s Mother’s first
cousin Tsar Ferdinand I of Bulgaria sat on the throne of
the neighbouring country, they’d become Romania’s
greatest opponent on the war to come.
• World War I : Ferdinand stood true to his new country,
rejecting the other, he was in conflict with the germans,
the germans succeeding to conquer Dobruja and
Wallachia, but they couldn’t have went further to
Moldovia because Ferdinand stoped them, he was
forced to sign a treaty, which he did not, while the
forces of the germans were invading Bulgaria,
Ferdinand mobilized his army and with the help of the
Triple Entente, the outcome of Romania’s effort was the
Union between Bessarabia, Bukovina and Transylvania
with the Kingdom of Romania in 1918.