On one side of the war were the [[Central Powers]]: [[Austria-Hungary]], [[Germany]], [[Bulgaria]], and the [[Ottoman Empire]]. The [[Allies]] consisted of the [[Britain|British]] and [[France|French Empires]], the Tsarist [[Russian Empire]](until 1917), [[Italy]], [[Japan]], [[Portugal]], and after 1917 the [[United States]]. | On one side of the war were the [[Central Powers]]: [[Austria-Hungary]], [[Germany]], [[Bulgaria]], and the [[Ottoman Empire]]. The [[Allies]] consisted of the [[Britain|British]] and [[France|French Empires]], the Tsarist [[Russian Empire]](until 1917), [[Italy]], [[Japan]], [[Portugal]], and after 1917 the [[United States]]. |