To legitimize his rule, tsar ivan iii claimed that russia was the "third rome." historically, this claim was reasonable because
a) he had been born in florence, italy.
b) he had defeated the byzantine empire.
c) his wife was the niece of the last emperor of the byzantine empire.
d) he ruled over an empire the size of the roman and byzantine empires.

The correct answer is C) his wife was the niece of the last emperor of the Byzantine Empire.

To help legitimize his rule, Tsar Ivan III claimed that Russia was the "Third Rome." Historically, this claim was reasonable because his wife was the niece of the last emperor of the Byzantine Empire.

Tsar Ivan III (1440-1505) also known as Ivan the Great, was the ruler of Russia that unified the country into Moscovite Russia and resisted the constant invasions intents by the Mongols. Ivan III conquered legendary rivals Tver and Novgorod. When his first wife died, he married princess Sophia, the niece of the last emperor of the Byzantine Empire.

i just did something on this guy a few days a go give me two minutes to find it in my notes.