On November 2, 1914, Cyprus was formally annexed by the United Kingdom after the Ottoman Empire entered the First World War on the side of the Central Powers. Many Cypriots, now British subjects, signed up to fight in the British Army, promised by the British that when the war finished Cyprus would be united with Greece. In 1923, under the Treaty of Lausanne, Turkey relinquished any claim to Cyprus. In 1925 Cyprus was declared a Crown colony.