reredos (rērˈdŏs) [key], ornamented wall or screen that rises behind the high altar of a church, forming a background for it. It may be placed against the apse wall at the extreme end or directly behind the altar, as in certain English churches where it serves to separate the choir and the retrochoir. Called dossal, or dorsal in its earliest form, it was a tapestry or a richly embroidered fabric suspended behind the altar. In the 11th and 12th cent. the reredos was generally a screen of gold, silver, or ivory adorned with sculptures in relief. It became a permanent architectural feature in the late Gothic in England and the Renaissance in Spain, where it was seen as a lofty decorative structure filling the entire width of the choir. Relief sculptures of the Passion and figures of angels and saints were enclosed by a rich framework of pilasters and pinnacles. Especially ornate were the marble and alabaster examples in Spain and those of polychromed and gilded wood in the baroque churches of Mexico. The reredos of Italy and Germany were primarily religious paintings within an architectural framework.