Winged altarpiece Winged altarpiece A winged altarpiece (also "folding altar") or winged retable is a special form of altarpiece (reredos, occasionally retable), common in Central Europe, in which the fixed shrine or "corpus" can be enclosed by two (triptych), four (pentaptych) or more (polyptych) movable wings. The technical terms are derived from : "trís" or "triple"; πέντε: "pénte" or "five"; πολύς: "polýs" or "many"; and πτυχή: "ptychē" or "fold, layer". Because the winged altar can display different scenes on weekdays, Sundays or holidays, based on the motifs and type of decoration (painted panels or reliefs), it is also called a liturgical altar.
Early Netherlandish painting both sides or with the reverse bearing family emblems, crests or ancillary outline sketches. In the case of single panels, the markings on the reverse are often wholly unrelated to the obverse and may be later additions, or as Campbell speculates, "done for the artist's amusement". Painting each side of a panel was practical since it prevented the wood from warping. Usually the frames of hinged works were constructed before the individual panels were worked on. Glue binder was often used as an inexpensive alternative to oil. Many works using this medium were produced but few survive today because of