The article presents the results of the analysis of “The Register of Ivan the Terrible’s oprichniki” – a document from the second half of the 16th century. It is precisely at this period that the present day three-part naming system: name – patronymic – surname was being established in Muscovy. The author attempts to prove that at this time the social status of a man could have been deduced from the formal exponents of his name: the number of its constituents, the structure of its patronymic, the fact that the name belongs to non-calendar or Christian names, and also from certain derivational markers.