As a vassal and later successor state to the khans, Ivan and his heirs commandeered the Mongol belief in absolute power of the sacred tsar, his holy mission to conquer, total ownership of the land and control of over all their ‘slaves’ – as all subjects, even nobles, were known. The imperial splendour and Orthodox mission of Constantinople were vital too, but it was the Mongol tradition that is probably key to understanding Russia right into the twenty-first century.
