The German Emperor (German: Deutscher Kaiser [ˈdɔʏtʃɐ ˈkaɪzɐ]) was the official title of the head of state and hereditary ruler of the German Empire. A specifically chosen term, it was introduced with the 1 January 1871 constitution and lasted until the official abdication of Wilhelm II on 28 November 1918.^[1] The Holy Roman Emperor is sometimes also called "German Emperor" when the historical context is clear, as derived from the Holy Roman Empire's official name of "Holy Roman Empire of the German Nation" from 1512.