The monograph is devoted to the study of one of the phenomena of medieval history - the Family, which got its name from the ancient name of the river. Diet - Seven. In the middle of the 10th century, a complex socio-political association of Semichs or Semites known from written sources was formed in the Seversky land, which played a prominent role under the blows of Vladimir's squads, and the remnants of the Semichs became part of the population of the Rurikovich state.