The two-
By 1480, Ivan III was strong enough to defy Mongol control and declare the autonomy of Moscow. To legitimize their new position, the princes of Moscow modeled themselves on the Mongol khans. Like the khans, the Muscovite state forced weaker Slavic principalities to render tribute previously paid to Mongols and borrowed Mongol institutions such as the tax system, postal routes, and census. Loyalty from the highest-
Another source of legitimacy for Moscow was its claim to the political and religious legacy of the Byzantine Empire. After the fall of Constantinople to the Turks in 1453, the princes of Moscow saw themselves as the heirs of both the caesars (or emperors) and Orthodox Christianity.