A corporal case or burse is the receptacle in which the folded corporal is carried to and from the altar, for convenience and and out of reverence. The corporal is a square white linen cloth, upon which the Sacred Host and chalice are placed during the celebration of Mass and it is important that it is protected from dirt or contamination.The spots of wax on the surface of this piece underline the need to cover up the corporal itself.
In Roman form the burse is ordinarily made of two pieces of cardboard about twenty-five centimetres (or ten inches) square, bound together at three edges, leaving the fourth open to receive the corporal. One outer side of the burse is of the same material and colour as the vestments with which it is used; the rest is lined with linen or silk. The use of the burse dates from the 12th century. When the corporal reached small dimensions, it was carried to the altar, sometimes in the missal, sometimes in a special receptacle, a box or bag, which finally took the present form of burse. Just when this custom began cannot be determined. <i>Chronicon vetus rerum Moguntinarum</i> (1140-1251) mentions a precious corporal-case; this may have been, however, only a box for the continual safe-keeping of the corporal. St. Charles Borromeo describes a <i>sacculus corporali</i> distinct from the case in which corporals were preserved (<i>Acta Mediolan</i>, 1683, I, 524). From the fourteenth to the seventeenth centuries the use of the burse spread, and in 1692 it was universally illicit to celebrate Mass without one (<i>Decreta S.R.C</i>, 1866, ad 2m).