The power of the shogun declines in 1441, after the 6th shogun, Ashikaga Yoshinori is assassinated. War (War of Onin) breaks out between factions of regional feudal lords and farmers over leadership of powerful feudal lords. This war lasts for 11 years, Kyoto, the main battleground, is in ruins, and the shogunate loses its power. Thereafter, feudal lords start fighting with other feudal lords in the area in order to expand their territory. From among them, Oda Nobunaga managed to almost conquer the whole of Japan. Nobunaga was the heir to a rural feudal lord of the southwestern region of Owari (western Aichi Prefecture). After he took over as head of the family, he gradually spread his rule over Owari by defeating Imagawa Yoshimoto of Suruga (Shizuoka Prefecture) and forming an alliance with Tokugawa Ieyasu of Mikawa (eastern Aichi Prefecture). He then unified all of Owari by defeating Oda Nobukiyo. After that, he invited Ashikaga Yoshiaki, who had been wandering the lands after losing power, and entered Kyoto. He elects him as shogun, and revives the Muromachi Shogunate. However, Yoshiaki deterred from Nobunaga’s intentions, governed on his own accord, and even tried to collaborate with other feudal lords to take down Nobunaga. Therefore he was banished.