Ruthenian 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.

Belarus, officially the Republic of Belarus, is a landlocked country in Eastern Europe. It is bordered by Russia to the east and northeast, Ukraine to the south, Poland to the west, and Lithuania and Latvia to the northwest. Covering an area of 207,600 square kilometres (80,200 sq mi) and with a population of 9.1 million, Belarus is the 13th-largest and the 20th-most populous country in Europe. The country has a hemiboreal climate and is administratively divided into six regions. Minsk is the capital and largest city; it is administered separately as a city with special status.