ENThe article analyses the problem of authenticity of one of the treaties between Grand Duke Jogaila of Lithuania and Duke Skirgaila of Trakai and the Teutonic Order concluded on 31 October 1382 and ceding the land of Samogitia (Lithuanian: Žemaitija) to the Teutonic Order. The treaty’s authenticity has been questioned in Belarusian research in recent years, as the Teutonic Order has been accused of forgery. In the article, it is shown that the surviving text is known from several copies, dating back to the last decade of the fourteenth century, and it fits the diplomatics of the Teutonic Order’s treaties of that time as well as the notion of power and the ruler’s rights of both sides. Therefore, there is no sufficient reason to consider the analysed document a forgery. Keywords: Teutonic Order, Teutonic Knights, Grand Duchy of Lithuania, Jogaila, Skirgaila, Samogitia, medieval diplomatics. [From the publication]