Central Powers, World War I coalition that consisted primarily of the German Empire and Austria-Hungary, the “central” European states that were at war from August 1914 against France and Britain on the Western Front and against Russia on the Eastern Front. Germany, Austria-Hungary, and Italy had been parties to a secret agreement, the Triple Alliance, from 1882 until World War I, but Italy entered the war in opposition to Germany and Austria-Hungary. The Ottoman Empire entered the war on the side of the Central Powers on October 29, 1914, as did Bulgaria on October 14, 1915.