ENIn the article "The scientific credo" describes the life and scientific path of the representative of the famous Belarusian Count family, of the archaeologist, ethnographer, curator of the museums, folklorist and patron Count Yaustakhe Tyshkevich. The activity for archaeological research on the Belarusian land, popularization of scientific knowledge, the preparation and publication of the monograph "The Discription of the Borisov Povet" are reflected in the article. The author considers the foundation of Vilna Anciently Museum and Archaeological Commission became the crown of the scientific working of Y. Tyshkevich.