Prussian Crusade - Invitation of The Teutonic Knights

Invitation of The Teutonic Knights

While in Rome, Christian of Oliva had made the acquaintance of Hermann von Salza, the Grand Master of the Teutonic Knights from 1209-39. With the permission of Duke Conrad of Masovia and the Masovian nobility, Christian requested aid from the Teutonic Knights against the pagan Prussians in 1226. Stability with the Prussians would then allow Conrad to pursue becoming High Duke of Poland. While Hermann was interested in the Polish offer, his focus was on assisting Emperor Frederick II with the Fifth Crusade. Because the Teutonic Order had recently been expelled from the Burzenland in the Kingdom of Hungary, Hermann also desired greater autonomy for his forces in future endeavors.

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. The Holy Roman Emperor gave his approval of the enterprise in the Golden Bull of Rimini of 1226, granting them Chełmno Land, or Culmerland, and any future conquests. The mission to convert the Prussians remained under the command of Bishop Christian of Oliva.

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. The agreement has been disputed by historians; the document has been lost and many Polish historians have doubted its authenticity and the Teutonic Order's territorial claims. However, recent studies by Polish historians have established the treaty's legitimacy. From the viewpoint of Duke Conrad, Chełmno was only to be used as a temporary base against the Prussians and future conquests were to be under the authority of the Duke of Masovia. Hermann von Salza saw the document as granting the Order autonomy in all territorial acquisitions, aside from allegiance to the Holy See and the Holy Roman Emperor. The Golden Bull of Rieti issued by Pope Gregory IX in 1234 reaffirmed the Order's control of conquered lands, placing them only under the authority of the Holy See.

The 14th century chronicler Peter von Dusburg mentioned eleven tribal districts in Prussia: Bartia, Culmerland (formerly under Polish control), Galindia, Nadrovia, Natangia, Pogesania, Pomesania, Samland, Scalovia, Sudovia, and Ermland. Peter estimated that while most tribes could muster about 2,000 cavalry, Samland could raise 4,000 cavalry and 40,000 infantry, while Sudovia had 6,000 cavalry and "an almost innumerable multitude of other warriors". In contrast, the Prussians of ravaged Culmerland could raise fewer troops than the other tribes. Galindia, a forested wilderness of lakes and rivers, also had a small population to raise troops from. Modern estimates indicate a total Prussian population of 170,000, smaller than that suggested by Peter von Dusburg.