Central Powers is a term used to refer to the Dual Alliance of Germany and Austria-Hungary, and the Ottoman Empire and Bulgaria, during World War I. They are so called because they all lay between Russia in the east and France and the United Kingdom in the west.
Germany and Austria-Hungary became allies on 7 October 1879, being joined subsequently (20 May 1882) (see Triple Alliance) by Italy, which however undertook secretly in 1902 not to honour its alliance commitments against Germany's principal adversary France.
Following the outbreak of European war in August 1914, the Ottoman Empire intervened at the end of October against Russia, provoking declarations of war by the Triple Entente powers - Russia, France and Britain.
Bulgaria, still resentful after its defeat in July 1913 at the hands of Serbia, Greece, Romania and Turkey, was the last nation to enter the war against the Entente, invading Serbia in conjuntion with German and Austro-Hungarian forces in October 1915.
Bulgaria signed an armistice with the Allies on 29 September 1918, following a successful Allied advance in Macedonia. Turkey followed suit on 30 October in the face of British and Arab gains in Palestine and Syria. Austria and Hungary concluded ceasefires separately during the first week of November following the disintegration of the Habsburg Empire, and Germany signed the armistice ending the war on the morning of November 11 after a succession of advances by US, British, French and Belgian forces in north-eastern France and Belgium.