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 was coined by Arthur Moeller van den Bruck as the title of his 1923 book Das Dritte Reich. It 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.
The term "Fourth Reich" has been used in a variety of different ways. Some neo-Nazis have used it to describe their envisioned revival of Nazi Germany, while others have used the term derogatorily, such as conspiracy theorists who have used it to refer to what they perceive as a covert continuation of Nazi ideals, and by critics who point out Germany exercises a dominant role in the European Union.
In terms of neo-Nazism, the Fourth Reich is envisioned as featuring Aryan supremacy, anti-Semitism, Lebensraum, aggressive militarism and totalitarianism. Upon the establishment of the Fourth Reich, German neo-Nazis propose that Germany should acquire nuclear weapons and use the threat of their use to re-expand to Germany's former boundaries as of 1914.
Based on pamphlets published by David Myatt in the early 1990s, many neo-Nazis came to believe that the rise of the Fourth Reich in Germany would pave the way for the establishment of the Western Imperium, a pan-Aryan world empire encompassing all land populated by predominantly European-descended peoples (i.e., Europe, Russia, Anglo-America, Australia, South America's Southern Cone, New Zealand, South Africa).