The Fourth Reich (German:Viertes Reich) is a theoretical future German empire that is the successor to Nazi Germany (1933–1945). The term Third Reich, originally coined by Arthur Moeller van den Bruck as the title of his 1923 book Das Dritte Reich, was used by the Nazis for propaganda purposes to legitimize their regime as a successor state to the retroactively-renamed First Reich (the Holy Roman Empire, 962–1806) and the Second Reich (Imperial Germany, 1871–1918). The terms First Reich and Second Reich were never used by historians.