Proper noun
First Reich
The Holy Roman Empire.
In recent times, the Regnum Teutonicorum has been referred to as the "First Reich," with Otto von Bismarck's Prussian-built empire called the "Second Reich" and Adolf Hitler's regime called the "Third Reich". Source: Internet
To use the terms "First Reich" and "Second Reich", as some commentators did in the post-war years, is generally frowned upon as accepting Nazi historiography. Source: Internet