Russians (Russian: русские, romanized: russkiye [ˈruskʲɪje] ) are an East Slavic ethnic group native to Eastern Europe. Their mother tongue is Russian, the most spoken Slavic language. The majority of Russians adhere to Orthodox Christianity, ever since the Middle Ages. By total numbers, they are the largest Slavic and European nation. Genetic studies show that Russians are closely related to Poles, Belarusians, Ukrainians, as well as Estonians, Latvians, Lithuanians and Finns. They were formed from East Slavic tribes, and their cultural ancestry is based in Kievan Rus'.
https://en.wikipedia.org/wiki/Russians