From a scattering of fishing villages on the Kanto plain far from the bustling capital of Kyoto and the centers of samurai power, medieval Edo transformed first into a castle town and military headquarters for the ambitious warrior Tokugawa Ieyasu and then into the early modern capital of the Tokugawa shogunate. In the early 1600s, driven by the logics of military defense and the societal supremacy of samurai, the warrior government built mechanisms and symbols of its power into the city. Edo Castle rose at its center and the rest of the city spun outward in a spiral pattern that shaped where people lived and how neighborhoods developed. As its physical footprint, economic pull, and political importance grew, early modern Edo catapulted over Kyoto and Osaka to become the largest city of the realm in mere decades.