Iberg Castle was built in 1240 by Heinrich von Iberg who was a vassal of the Prince-Abbot of St. Gallen. The castle was briefly conquered in 1249 following the Toggenburg fratricide and again in 1290 during the rule of the anti-Abbot Konrad von Gundelfingen in St. Gallen. It was damaged during the Appenzell Wars in 1405 and soon thereafter rebuilt. During the conflicts leading to the Battles of Villmergen (from 1699-1712), the castle was besieged in 1710. After the Treaty of Baden in 1718 it was given back to the Abbot.