The Pan-German movement had coalesced in the 1890s among German critics of imperial timidity, and it had gained substantial influence by the eve of World War I. It urged, among other things, the uniting of all ethnic Germans ("Deutschtum"), regardless of existing state borders; reduction of "un-German" (Slav, Catholic, Jewish) cultural influence; and creation of "lebensraum" for Germany by colonial annexation. Baranowski 2011, 42-45; Wertheimer 1924, 3-4. This map illustrates "The Pangerman Plot Unmasked," a 1916 work by a French journalist which became a sensation, particularly after its translation into English the following year.
The message was clear: Pangermanism was not merely a German claim "to annex only the regions inhabited by dense masses of Germans, on the border of the Empire," or "to gather within the same political fold the peoples who are more or less Germanic by origin" (albeit "quite inadmissible"). "Pangermanism is more than that. It is really the doctrine, of purely Prussian origin, which aims at annexing all the various regions, irrespective of race or language, of which the possession is deemed useful to the power of Hohenzollerns." Cheradame 1917, 1-2.
The collection includes a number of maps related to Pangermanism.