him. Ieyasu left some western daimyo unharmed, such as the Shimazu clan, but others were completely destroyed. Toyotomi Hideyori (the son of Hideyoshi) lost most of his territory which were under management of western daimyo, and he was degraded to an ordinary daimyo, not a ruler of Japan. In later years the vassals who had pledged allegiance to Ieyasu before Sekigahara became known as the fudai daimyō, while those who pledged allegiance to him after the battle (in other words, after his power was unquestioned) were known as tozama daimyō. Tozama daimyō were considered inferior to fudai daimyō. Shōgun (1603–1605) On March 24, 1603, Tokugawa Ieyasu received the title of shōgun from Emperor Go-Yōzei. Ieyasu was 60 years old. He had outlasted all the other great men of his times: Oda Nobunaga, Takeda Shingen, Toyotomi Hideyoshi, and Uesugi Kenshin. As shōgun, he used his remaining years to create and solidify the Tokugawa shogunate, which ushered in the Edo period, and was the third shogunal government (after the Kamakura and the Ashikaga). He claimed descent from the Minamoto clan who had founded the Kamakura shogunate, by way of the Nitta clan. His descendants would marry into the Taira clan and the Fujiwara clan. The Tokugawa shogunate would rule Japan for the next 260 years. Following a well established Japanese pattern, Ieyasu abdicated his official position as shōgun in 1605. His successor was his son and heir, Tokugawa Hidetada. There may have been several factors that contributed to his decision, including his desires to avoid being tied up in ceremonial duties, to make it harder for his enemies to attack the real power center, and to secure a smoother succession of his son. The abdication of Ieyasu had no effect on the practical extent of his powers or his rule; but Hidetada nevertheless assumed a role as formal head of the shogunal bureaucracy. Ōgosho (1605–1616) Construction of Edo castle In 1605, Ieyasu, acting as the , remained the effective ruler of Japan until his death. Ieyasu retired to Sunpu Castle in Sunpu, but he also supervised the building of Edo Castle, a massive construction project which lasted for the rest of Ieyasu's life. The result was the largest castle in all of Japan, the costs for building the castle being borne by all the other daimyo, while Ieyasu reaped all the benefits. The central donjon, or tenshu, burned in the 1657 Meireki