Roman Catholic Diocese of Saint Gallen in the context of "Appenzell Ausserrhoden"

The Abbey of Saint Gall (German: Abtei St. Gallen) is a dissolved abbey (747–1805) in a Catholic religious complex in the city of St. Gallen in Switzerland. The Carolingian-era monastery existed from 719, founded by Saint Othmar on the spot where Saint Gall had erected his hermitage. It became an independent principality between 9th and 13th centuries, and was for many centuries one of the chief Benedictine abbeys in Europe. The library of the Abbey is one of the oldest monastic libraries in the world.

The city of St. Gallen originated as an adjoining settlement of the abbey. The abbey was secularized around 1800, and in 1848 its former church became St. Gallen Cathedral, the seat of the Diocese of Saint Gallen. Since 1983 the abbey precinct has been a UNESCO World Heritage Site.

The Stiftskirche St. Gallus und Otmar (Collegiate Church of St. Gall and Otmar) is a Roman Catholic church in the city of St. Gallen, Switzerland. Once part of the Abbey of St. Gall, it has been the cathedral of the Diocese of St. Gallen since 1847. It is considered one of the last great sacred structures of the Baroque era, and is a UNESCO World Heritage site.