Located 17 meters above sea level, Reichenau Abbey had a vineyard established there. In late May/early June 1415, Pope John XXIII was held here as a prisoner of the Council of Constance after he had been captured in Freiburg while fleeing from Constance to Burgundy. In 1421, the city took possession of the castle and the associated Ammann office (municipal administration and lower jurisdiction) as collateral, and in 1538, it became the city’s permanent property.