The word "reich" in German translates loosely into "empire" in English but more closely aligns with the word for "realm", i.e. the area under which a nation-state exercises some sort of authority. During the Holy Roman Empire, this authority was quite loose with the Emperor serving as a nominal figurehead over the famous "patchwork" of German states that stretched from Italy to Denmark. Unlike most modern constitutional monarchies where succession from father to son is guaranteed by law, the Holy Roman Emperor was nominally elected by the Kurfürsten, or prince-electors, to the office of King of the Romans until he could be officially crowned by the Pope. All of this was eventually done away with and princely elections became a mere rubber stamp for the House of Habsburg in alignment with other centralized European states save for the King of Poland. This left Germany with a history of crowned republics that would last until the disbandment and mediatiziation of the Holy Roman Empire under Napoleon. This concluded the First Reich, which did indeed last for a thousand years.

The nominal Second Reich was the German Empire established by the House of Hohenzollern after Wilhelm I was offered the Crown by the German princes in the Hall of Mirrors at Versailles in 1871. This was the conclusion of a longstanding policy of the Hohenzollerns to refuse a "crown from the gutter", i.e. rule from popular authority, after the Frankfurt Parliament of 1848 attempted to crown an extremely reluctant Frederick William IV as "Emperor of the Germans" in 1849. The Second Reich would last until the defeat of Germany and the subsequent abdication of Wilhelm II in 1918 at the conclusion of the First World War.

Germany's defeat in the First World War led to a period of instability under the Weimar Republic. Initially inaugurated by virtual accident under the unilateral proclamation of Philipp Scheidemann, the loss of the war and the crown -- Prince Max of Baden, the then prime-minister, exclaimed that he "hated a republic like sin" -- led to a polarization of politics under the far-right and far-left. The far-right soon adopted the concept of the Dolchstoßlegende, roughly translated as the "stabbed in the back myth", which stated that Germany had been betrayed by a so-called fifth column within the nation. This fifth column was initially amorphous and its vitriol was directed at virtually anyone the crowd disliked: hungry Jewish capitalists, corrupt and bungling aristocrats and communist agitators were all popular targets of public ire. Hitler's rise to power therefore took advantage of the dolchstoßlegende in order to declare his administration and party the arbiters of a new reich, the Third Reich, which would last for a thousand years as had the First Reich. Hitler's Reich was simply the domain of the German people and could take on any form of elected or declared head of state it chose.