Can classical political theories of mixed constitution from Polybius to Cicero help us shed new light on Russian politics? In order to so, this article first considers political structures of such non-parliamentary republics as medieval Novgorod and Venice, while choosing Constantinople as a basis for their comparison. Second, using Anthony Kaldellis's recent book that has reinterpreted Byzantium in terms of the classical theory of res publica, it analyzes the question of auctoritas in ancient republican Rome and then imperial Constantinople. Third, the author employs Giorgio Agamben's book on the state of exception, in order to see how mechanisms of power and authority that the Roman emperors had employed might help us interpret anew the phenomenon of tsardom, given that Ivan the Terrible was the first in Russia to be crowned as tsar, that is, Ceasar. This might have a lasting significance even for present day politics.