During the Kamakura period, the Kamakura shogunate awarded the Sasaki clan control over Izumo and Oki Provinces, and the cadet branch of the Sasaki which eventually controlled Izumo during the Muromachi period was the Kyōgoku clan.

The Kyōgoku established their stronghold on Gassan, which appears to have already had an ancient fortification from the Heian period.

[3][4] However, the Kyōgoku were soon overthrown by one of their vassals, Amago Tsunehisa, who through a combination of cunning and ruthlessness, expanded his territory by confiscating lands of temples, shrines and his weaker neighbors.

After his death in 1540, his successor, Amago Haruhisa could not command the same loyalty, and local lords began to defect to the Ōuchi, or to the rising power of the Mōri clan.

The Tokugawa shogunate awarded it to his general Horio Tadauji as the seat of the Matsue Domain.