The corporal (arch. corporax, from Latin corpus "body") is a square white linen cloth, now usually somewhat smaller than the breadth of the altar, upon which the chalice and paten, and also the ciborium containing the smaller hosts for the Communion of the laity, are placed during the celebration of the Catholic Eucharist (Mass).
It may reasonably be assumed that something in the nature of a corporal has been in use since the earliest days of Christianity. Naturally it is difficult, based on the extant records from the early church, to distinguish the corporal from the altar-cloth. For instance, a passage of St. Optatus (c. 375), where he asks, "What Christian is unaware that in celebrating the Sacred Mysteries the wood [of the altar] is covered with a linen cloth?" (ipsa ligna linteamine cooperiri) leaves us in doubt to which he is referring. This is probably the earliest direct testimony; for the statement of the Liber Pontificalis, "He (Pope Sylvester I) decreed that the Sacrifice should not be celebrated upon a silken or dyed cloth, but only on linen, sprung from the earth, as the Body of our Lord Jesus Christ was buried in a clean linen shroud" cannot be relied upon. Still, the ideas expressed in this passage are found in an authentic letter of St. Isidore of Pelusium and again in the "Expositio" of St. Germanus of Paris in the sixth century. Indeed they lasted through the Middle Ages.
It is quite probable that in the early centuries only one linen cloth was used which served both for altar-cloth and corporal. This would have been of large size and doubled-back to cover the chalice. Much doubt must be felt as to the original use of certain cloths of figured linen in the treasury of Monza which Barbier de Montault sought to identify as corporals. The corporal was described as palla corporalis, or velamen dominic mens, or opertorium dominici corporis, etc.; and it seems generally to have been of linen, though we hear of altar-cloths of silk, or of purple; (a coloured miniature in the tenth-century Benedictional of St. Thelwold also seems to show a purple altar-covering), or of cloth-of-gold. In some of these cases it seems difficult to decide whether altar-cloth or corporal is meant.