Re-established by Bolesław I the Brave in the days of the medieval Piast dynasty, Santok became an important border fortress of Greater Poland and seat of a castellany. An attack by Duke Barnim I of Pomerania in 1251 was repelled. During the 13th century however, the strategically important hill fort became the object of claims raised by the Ascanian margraves of Brandenburg, who intended to enlarge their territories in the "Neumark" region east of the Oder river. Upon the marriage of Margrave Conrad of Brandenburg-Stendal with Constance, daughter of the deceased Duke Przemysł I of Greater Poland, in 1260, Santok passed to the margraviate as part of her dowry. Once again reconquered by the Polish duke Przemysł II, it finally was incorporated by Brandenburg upon his death in 1296.