In this article the author examines the news of European cosmographers of the first quarter of the 16th century about the lands of Eastern Europe discovered at that time. In this article the author examines the news of European cosmographers of the first quarter of the sixteenth century about the lands of Eastern Europe discovered at that time. In the cosmographic work of the Polish author Mathias de Miechow, who relied on the observations of his predecessors – Julius Pomponius Laetus, Pius II, as well as Catalan, Genoese, Venetian cartographers of the fourteenth and fifteenth centuries – a significant part of the data about the most important geographical objects in Eastern Europe, contained in the works of ancient scholars, was rejected or clarified. In the short time since the first publication of Mathias de Miechow's book, the view he expressed on the geography of Eastern Europe had become predominant, if not universally accepted. Its positive and even enthusiastic perception is to be found in the closely related works on Muscovy by European authors such as Albertus Campensis, Paolo Giovio, Ulrich von Gutten. In particular, these authors confirmed the non-existence of of the so-called Riphean and Hyperborean Mountains, the existence of which had been reported by the most eminent scholars of antiquity; they had also reinterpreted reports of their predecessors about the sources of the great rivers of this region, about peoples and tribes which inhabited it.However, as the author emphasises, these new data about geography and ethnography of Eastern Europe, obtained by humanists-cosmographers should be considered not only as a kind of manifestation of the general processes of global reappraisal of classical inheritance but as an important step in the development of Renaissance self-consciousness revealed in the affirmation of intellectual superiority of Modern epoch in comparison with Antiquity.