Charles I (English: Charles Francis Joseph Louis Hubert George Otto Mary, German: Karl Franz Joseph Ludwig Hubert Georg Otto Marie, Hungarian: IV. Károly or Károly Ferenc József) was Emperor of Austria and King of Hungary, thus he was the ruler of the Austrian-Hungarian Empire.
He was born on 17 August 1887 in the Castle of Persenbeug in Lower Austria, and died 1 April 1922 in Vienna, Austria. He was the son of Archduke Otto Francis of Austria (1865-1906) and Princess Maria Josepha of Saxony (1867-1944).
He inherited the Austrian-Hungarian throne upon the death of Francis Joseph I on 21 November 1916. By then, Austria-Hungary was involved in the second German-French war on the side of the German Empire, a war which was ended in 1918.
He married on 21 October 1911 at the Schwartzau Castle to Princess Zita of Bourbon-Parma (1892-1989), a daughter of Duke Robert I of Parma and Princess Mary Antonia of Portugal. Charles and Zita had the following issue:
Otto (1912-2011), who succeeded his father as Otto I
Felix (born 1916)
Charles Louis (1918-2007)