The name, "Edo," first appeared in a document written during the Kamakura period. Edo Castle was constructed around the middle of the 15th century by Ōta Dōkan (1432-1486), a leading Kantō-region vassal of the Uesugi family who ruled in the Kantō-region, and the castle town was then formed.

On August 1, 1590 (Tenshō 18), Tokugawa Ieyasu, who would later found the Tokugawa Shogunate, entered Edo. Generally speaking, the Edo that now comes to mind is the city developed by Tokugawa Ieyasu, and his successors Tokugawa Hidetada and Tokugawa Iemitsu. Ieyasu began by making repairs to Edo Castle which had become very much run-down. Subsequently, he developed a vast city with the castle at the center. In other words, Edo started life very much as a military town.