Austria–Germany relations Austria–Germany relations Relations between Austria and Germany are close, due to their shared history and language, with German being the official language and Germans being the largest ethnic group of both countries. Modern-day Austria and Germany were united until 1866: their predecessors were part of the Holy Roman Empire and the German Confederation until the unification of German states under Prussia in 1871, which excluded Austria. In 1918 after the end of World War I, Austria renamed itself the Republic of German-Austria in an attempt for union with Germany but this was forbidden by the Treaty of Saint-Germain-en-Laye (1919). In
States of Austria arable terrain. The other five states, in contrast, are located in the Alps and thus are comparatively unsuitable for agriculture. Their terrain is also relatively unfavourable to heavy industry and long-distance trade. Accordingly, the population of what now is the Republic of Austria has been concentrated in the former four states since prehistoric times. Austria's most densely populated state is the city-state of Vienna, the heart of what is Austria's only metropolitan area. Lower Austria ranks only fourth with regard to population density even though it contains Vienna's suburbs; this is due to large areas of land being predominantly agricultural.