Alt-Wädenswil Castle (Ruin) (Richterswil)

Alt-Wädenswil is a castle ruin on a hill west of the Burghalden railway station of the Swiss Southeastern Railway in the municipality of Richterswil, in the canton of Zurich.

In a foundation charter of Fahr Abbey, the Barons of Wädenswil (Wadinswilere) were first mentioned in a document in 1130. The barons built their residence, Alt-Wädenswil Castle, in the 13th century. The castle was first mentioned in writing in 1265. The baronial tower, built before 1200, is the oldest part of the castle. Its outer walls are made of mighty boulders. In 1287, the last baron Rudolf III, lacking descendants, sold the lordship of Wädenswil – today's municipalities of Wädenswil, Richterswil, Schönenberg ZH, Hütten ZH and Uetikon am See – to the Johanniterhaus Bubikon. Wädenswil became a commandery of the Knights Hospitaller. The Johanniterhaus was built in the 14th century as an order castle with a new moat. The thirteen rooms with dormitory, refectory, convent, a pilgrim's hostel and a chapel served primarily for the commandery administration. In the 15th century, the entire castle grounds were surrounded by a curtain wall fortified with towers.

After the Reformation, the Knights Hospitaller sold the lordship of Wädenswil with all rights to the Canton of Zurich in 1549. Wädenswil became a bailiwick. Wädenswil Castle was built for the bailiff from 1550 to 1555. The castle had to be demolished after a decision by the Tagsatzung in 1557, because Schwyz felt threatened by the enlarged city-state of Zurich. In 1900, an initiative committee acquired the castle grounds and founded the Foundation for the Preservation of Alt-Wädenswil Castle in 1902. The first excavation work took place from 1901 to 1904, with further excavation campaigns from 1938 to 1941 and in 1983.