Constantine I, King of the Hellenes, ruled Greece from 1913-1917 and from 1920-1922.
He was born 2 August 1868 at Athens. He married, on 27 October 1889 at Athens, Princess Sophie of Prussia (1870-1932).
He succeeded to the throne of Greece on 18 March 1917 following his father’s assassination.
He left Greece on 11 June 1917 and was succeeded to the throne by his second son Alexander as acting King. Alexander died 25 October 1920 and following a plebiscite, Constantine returned as king 19 December 1920.
He abdicated the throne on 27 September 1922, and was succeeded by his eldest son, George II.
He died 11 January 1923 at Palermo.