Ages, many such came to be known as counties or Grafschaften, the territory of a Graf (count) within the Holy Roman Empire. Such a count or would originally have been an appointed governor, but the position generally became an hereditary vassal princedom, or fief in most of continental Europe. Nazi period The term Gau was revived in German historical research in the 18th and 19th centuries, and was considered an ancient administration structure of Germanic peoples. It was adopted in the 1920s as the name given to the regional associations of the Nazi Party (NSDAP). Each Gau denoted an administrative region, created by a party statute dated 22 May 1926. Each Gau was headed by a Gauleiter. The original 33 Gaue were generally coterminous with the Reichstag election districts of the Weimar Republic, based on the constituent states (Länder) and the provinces of Prussia. Following the suppression of the political institutions of the Länder in the course of the Nazi Gleichschaltung process and the appointment of Reichsstatthalter (Reich Governors) in 1933, the Gaue became the de facto administrative regions of the government and each individual Gauleiter had considerable power within his territory. Reichsgaue With the beginning of the annexation of neighbouring territories by Nazi Germany in the late 1930s, a new unit of civil administration, the Reichsgau, was established. German-speaking territories annexed to Germany from 1938 were generally organised into Reichsgaue. Unlike the pre-existing Gaue, the new Reichsgaue formally combined the spheres of both party and state administration. Following the annexation of Austria in 1938, the country, briefly renamed "Ostmark" between 1938 and 1942, was sub-divided into seven Reichsgaue. These had boundaries broadly the same as the former Austrian Länder (states), with the Tyrol and Vorarlberg being merged as "Tyrol-Vorarlberg", Burgenland being divided between Styria and "Lower Danube" (Niederdonau, the renamed Lower Austria). Upper Austria was also renamed "Upper Danube" (Oberdonau), thus eliminating the name of "Austria" (Österreich in German) from the official map. A small number of boundary changes also took place, the most significant of which was the massive expansion of Vienna's official territory, at the expense of "Lower Danube". Northern and eastern territory annexed from the dismembered Czechoslovakia were mainly organised as the Reichsgau of Sudetenland, with territory to the south annexed to the Reichsgaue of Lower and Upper Danube. Following the Axis invasion of Poland in 1939, territories of the Pomeranian and Poznań voivodeships as well