Wikipedia
Severians
The Severians or Severyans or Siverians (; ; ) were a tribe or tribal union of early East Slavs occupying areas to the east of the middle Dnieper river, and Danube. They are mentioned by the Bavarian Geographer (9th century), Emperor Constantine VII (956-959), by Khazars ruler Joseph (c. 955), and in the Primary Chronicle (1113).