Why "Free State"?
In Germany the term Free State (in German "Freistaat") comes from the 19th century as a German word for republic. After the German Revolution of November 1918, when Imperial Germany became the Weimar Republic, most of the German states within the German Reich called themselves a Free State. Others used expression like Republik or Volksstaat ("people's state").
Nowadays, 3 of the 16 German Länder use the expression “Freistaat”: Bavaria (Freistaat Bayern), Saxony (Freistaat Saxen), and Thuringia (Freistaat Thüringen).
Source: Wikipedia
