The architecture of the Third Reich was consciously eclectic, which did not result from its flexibility but rather from a desire to multiply means of persuasion. On the example of Poznań, as the capital of the Gau Wartheland, used forms and their relationship to the existing Prussian tradition can be considered from the perspective of the tasks set for art – Nazification and Germanisation of the areas incorporated into the Third Reich. These ideological foundations of Nazi architecture in Poznań are confirmed primarily by the reconstruction of the former Imperial Castle and the plan for the People’s Hall in the Citadel.