The German Emperor (German: Deutscher Kaiser) was the official title of the head of state and hereditary ruler of the German Empire. A specifically chosen term, it was used between the 18 January 1871 proclamation of King of Prussia and President of the North German Confederation Wilhelm I as "Deutscher Kaiser" and the official abdication of Wilhelm II on 28 November 1918. The Holy Roman Emperor is sometimes also called "German Emperor" when the historical context is clear.