In 1230, the Treaty of Kruszwica was supposedly signed, according to which Konrad granted them (and Order of Dobrzyń) Chełmno Land. This document does not exist anymore, and some sources say that the Order had forged it.
Brother Konrad had offered and promised to furnish brother Hermann, Honorable Master of the Holy Hospital of St. Mary of the Germans in Jerusalem (Teutonic Order)...with the Chełmno Land between his march and the Prussians and equip them (T.O.) well, so they may take Preussenland (Terra Prussiae) in possession... we recognize the fact, that this land is included in the realm of the empire, we trust the judgement of the Master... we recognize all land in Prussia as an ancient right of the empire ...".
^^^one of the worst events in Poland history^^^