Reredos. A carved or painted screen behind the altar. Very few medieval ones survive; those that do, are often not in their original churches, but brought in by an 18th century antiquarian or 19th century Anglo-catholic vicar. Their subjects, usually saints or the crucifixion, made them an obvious prey for the Anglican reformers of the 1540s. No evidence suggests that many survived to incur the wrath of the puritans 100 years later; Dowsing does not mention coming across any in his journal. However, it is possible that decalogue boards were painted over some of them.
Many churches have 19th century reredoses, produced under the influence of the Oxford Movement. They are of varying quality, and different ones appeal to the taste of different people.
Technically, reredoses where candlesticks may be placed are retables, although the distinction between the two is rather hazy.