A picture of some sacred subject painted on the wall or suspended in a frame behind the altar, or a group of statuary on the altar. In the Middle Ages, instead of a picture or group, the altar-piece consisted in some churches of embossed silver or gold and enamelled work set with jewels. Sometimes the piece was set on the altar itself. If the altar stood free in the choir, and the altar-piece was to be seen from behind as well as from before, both sides were covered with painting (Norton, Church Building in the Middle Ages). The decorated screen, retable or reredos is also called an altarpiece. (See ALTAR-SCREEN.)