Old Russians
According to some historians, the Old Russian people (Russian: Древнерусская народность, romanized: Drevnerusskaya narodnost', Ukrainian: Давньоруська народність, romanized: Davnʹorusʹka narodnistʹ) were a unified ethnic group that emerged from East Slavic tribes of the Kievan Rus. The foundations for this theory were laid by Sergei Tokarev and further developed by Boris Rybakov and Pyotr Tretyakov.