Why was Nazi Germany called the Third Reich?

The designation "Third Reich" was used by the Nazi regime to position Adolf Hitler’s government as the historical successor to two previous German empires, thereby lending a sense of legitimacy and historical continuity to his rule.12

The three "Reichs" (empires) are defined as follows:

• First Reich: The Holy Roman Empire, which existed from 800 to 1806.13
• Second Reich: The German Empire, which lasted from 1871 to 1918.14
• Third Reich: The Nazi regime in Germany from 1933 to 1945.14

The term originated in 1923 with the publication of Das Dritte Reich by cultural critic Arthur Moeller van den Bruck. While Moeller’s work was not explicitly national socialist, it advocated for a conservative, nationalist vision of a final German empire. Hitler adopted the concept to frame his "thousand-year Reich" as the natural conclusion of German history, tracing its roots back to the coronation of Charlemagne. It is important to note that this retrospective classification was a political construct; the inhabitants of the earlier periods would not have recognized these labels.2