Satomi clan
Satomi Yoshiyori, virtually independent lord of all of the Bōsō Peninsula during the Sengoku Period, erected Tateyama Castle in 1580 to guard the entry to Edo Bay and the southern portions of his domains. After the Satomi clan was destroyed by the Tokugawa shogunate in 1614 and Tateyama Domain suppressed, the castle was allowed to fall into ruin.