ENThe article is trying to recreate the route and the aim of the Byzantine embassy to the Grand Dukes of Moscow and Lithuania in 1415. It proves the hypothesis that missions, mentioned by Vytautas in his encyclical gramota and by Jan Długosz in his Annales seu cronicae incliti Regni Poloniae, were the same embassy, and that it was not related to the well-known mission of Theodore Chrysoberges to Władysław II Jagiełło at the same year. The supposed aims of the mission were connected with the creation of the separate Kyiv metropolis for Vytautas’ Orthodox subjects, as well as with the dynastic alliance between the children of Vasily I of Moscow and Manuel II Palaiologos that concerned Vytautas’ interests.