At the beginning of the Kamakura period, the shogunate established the powerful Kōno clan as governors (shugo) over the entire Iyo Province, including Saijō. The Kōno had long held power over the region as manorial lords of the Saijō area. However, in 1342, Ashikaga Takauji ordered the invasion of Iyo Province by the subordinate Hosokawa clan as part of a bid to consolidate the shogunate's power over all of Shikoku. The Hosokawa clan assumed control over a large portion of the area that would last until the Warring States Period, and Saijō was ruled by proxy by the Ishikawa clan from Takakogi Castle in the present day Sunouchi district.