Best wishes, John Green. After Basil the Blind came the real man who expanded Moscow's power, Ivan III, later known as Ivan the Great. First, he asserted Russian independence from the Mongols and stopped paying tribute to the Khan, after the Khan had named him Grand Prince, of course. Then, Ivan purchased, negotiated for, or conquered multiple appendages, thus expanding Muscovite power even more. Ivan later declared himself sovereign over all Russians and then married the niece of the last Byzantine emperor, thus giving him even more legitimacy. And he took the titles autocrat and czar, which means Caesar. Basically, Ivan created the first centralized Russian state, and for doing that, he probably deserves the title the Great.