ENOwing to its tolerant domestic policy, the Grand Duchy of Lithuania had become an asylum for various religious-ethnic groups persecuted in various parts of Europe, including the Golden Horde and Crimean Tatars. The beginnings of Tatar settlement date back to Vytautas’ times (the turn of the 14th century). Entering the community of the Grand Duchy of Lithuania, the Tatars conformed to sociocultural processes which the community was undergoing at the time. An integral part of the processes was, among others, the process of shaping the anthroponymic system. The first stage of shaping Tatar last names was characterized by domination of the East Slavic model, i.e. patronymic structures -owicz/-ewicz. When in the lGth century the entire nobility of the Grand Duchy of Lithuania was exposed to Polonization, toponymic formations with the suffix -ski began to appear and stabilize. It is wortli pointing to a phenomenon of interaction (particularly in the lG11' and 17th century anthroponymy) between the Tatar language and Slavic languages, which came down to the occurrence of similar or identical suffixes in Tatar first names (e.g. -asz, -esz, -ysz, -sza, -aj, -ej, -ak, -czuk) as well as the presence of numerous hypocorisms (mainly in the l6th century) formed by the East Slavic suffix -ko (e.g. Alejko, Isupko, Nurko).