Ivan the Great, also known as Ivan III, was a Grand Prince of Moscow who ruled from 1462 to 1505. He is best known for unifying the Russian principalities and laying the foundation for the Russian state. Under his leadership, Moscow expanded its territory and gained independence from the Mongol Empire. Ivan the Great is credited with significant reforms, including the establishment of a centralized government and the introduction of a new legal code. He also built the Kremlin, which became a symbol of Russian power. His reign marked the beginning of the rise of Russia as a major European power.