During the Kamakura and Muromashi periods, southern end of Oshima Peninsula was put under the influence of the Ando clan in Honshu (Refer to Donan Juni Kan [12 castles of the Oshima Peninsula] and Watarito [migratory group].)
鎌倉時代・室町時代の間には本州の安東氏の影響下に置かれた（道南十二館・渡党参照）。