Hermann met with Frederick II at Rimini and suggested that the subjugation of the Prussians would make the Holy Roman Empire's borders easier to defend against invaders [REF].
Before beginning the campaign against the Prussians, the Teutonic Knights allegedly signed the Treaty of Kruszwica with the Poles on June 16, 1230, by which the Order was to receive Culmerland and any future conquests, similar to the terms of the Golden Bull of Rimini.