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.
St John Altarpiece (Memling) it presents a narrative, meant to emulate a vision the donors or viewers would experience when viewing the inside panels. Unlike most altarpieces of these types, Memling's fails to present a single unifying iconographical focus and is quite generalized with themes that seem unsuited for its specific location, according to Blum. She speculates the donors may have chosen the specific iconography, which "celebrated intercessory saints on the interior". It is an unusual painting in that it seems to "have served a double function: that of personal propitiation and that of public altarpiece, which portrayed the role of the religious community