Constantine I of Greece (1868-1923), king of Greece (1913-1917, 1920-1922). The son of King George I, he was born in Athens and educated at Greek and German military academies. In 1889 he married Sophia, princess of Prussia and sister of German Emperor William II. Constantine had served in the German army, and in 1897 led a Greek force in a short but disastrous war against Turkey. He later led the Greeks in the First Balkan War (1912-1913), which increased Greek territory. He ascended the throne on the death of his father in 1913. During World War I, Constantine was pro-German, whereas Eleutherios Venizelos, the Premier, wished to join the Allies. The struggle resulted in a policy of Greek neutrality until September 1916, when an Allied naval blockade caused Greece to declare war on Germany. Constantine, under Allied military pressure, abdicated on June 12, 1917, in favour of his son, Alexander. Three years later, after Alexander's death, Constantine was restored as king by a plebiscite. In September 1922, however, the Greek defeat in the renewed war with Turkey forced Constantine to abdicate again, leaving the throne to his eldest son, George II. Constantine died in exile in Italy.