Ivan the Terrible’s First Letter to Andrej Kurbskij is the principal document from which the political doctrine of the first Russian Tsar used to be reconstructed. However many of the sources on which this voluminous piece of literature is based have not been identified and commented on. The paper lists several translated Byzantine texts that appeared in the First Letter in the form of aphorisms. The function of those aphorisms confirms the conclusion that was partly suggested by more recent experts, i.e. that the Kurbskij-Groznyj discussion developed on a highly abstract level. They discussed the attributes of the ideal governor and neither of them proposed social innovations in the actual state structure.

The article is written in Russian.