abbey, monastic house, especially among Benedictines and Cistercians, consisting of not less than 12 monks or nuns ruled by an abbot or abbess. Many abbeys were originally self-supporting. In the Benedictine expansion after the 8th cent., abbeys were often important centers of learning and peaceful arts and, like Fulda, were sometimes the nuclei of future towns. The buildings surround a church and include a dormitory, refectory, and guest house, all surrounded by a wall. The courtyard, derived from the Roman atrium, was a usual feature, as was the cloister or arcade surrounding the court. Cluniac abbeys were always ornate, Cistercian ones notably bare. The Carthusians with their special polity developed an altogether different structure called the charterhouse.