Based on archaeological evidence, it seems German colonization of the region started in the middle of the 12th century during the reign of King Géza II of Hungary.
[7] The Teutonic Knights began building wood-and-earth forts in the area and they had constructed five castles (quinque castra fortia):[6] Marienburg, Schwarzenburg, Rosenau, Kreuzburg, and Kronstadt,[7] some of which were made of stone.
Grand Master Hermann von Salza attempted to loosen the Order's ties to the Hungarian crown by drawing closer to the Papacy.
[10] The confusing status of the Teutonic Knights within the Kingdom of Hungary led Hermann von Salza to insist upon autonomy before committing the military order to Prussia.
[11] At the Conference of Lutsk in 1429, Sigismund, Holy Roman Emperor and King of Hungary, suggested that the Teutonic Knights defend the region during the Ottoman wars in Europe.