reredoses

Refers to relatively large ornamented walls, screens, or other structures located above and behind the high altar of a Christian church. A reredos may be placed against the apse wall or directly behind the altar. A reredos may form part an altar screen. The term was in common use by the 15th century, and was derived from an Anglo-French word meaning 'rear' or 'behind.' It grew out of the dossal, which was a tapestry or painting on the wall behind the altar. In church design, beginning in the late 11th century, the bishop's seat and choir stalls were brought forward from the altar wall, and the reredos was erected as a screen between them and the congregation. In certain English churches it served to separate the choir and the retrochoir. In time the reredos was made of precious materials and was heavily decorated, often with carvings, niches, sculptures, paintings and tapestries. In Spanish churches the reredos grew to be as wide as the nave and reaching to the vaulting of the roof. It is distinct from a 'retable'; while the reredos typically rises from ground level behind the altar, the retable is smaller, standing either on the back of the altar itself or on a pedestal behind it. Many altars have both a reredos and a retable. In architecture the term 'reredos' may also refer to a screen or partition wall in other contexts, for example, to the wall forming the back of a fireplace or open hearth in ancient halls.