Ruthenian (Belarusian: руская мова; Ukrainian: руська мова; Ruthenian: руска(ѧ) мова; also see ) is an exonymic linguonym for a closely-related group of East Slavic linguistic varieties, particularly those spoken from the 15th to 18th centuries in the Grand Duchy of Lithuania and in East Slavic regions of the Polish–Lithuanian Commonwealth. Regional distribution of those varieties, both in their literary and vernacular forms, corresponded approximately to the territories of the modern states of Belarus and Ukraine. By the end of the 18th century, they gradually diverged into regional variants, which subsequently developed into the modern Belarusian, Ukrainian, and Rusyn languages.