§ 57. The altar itself, as can be seen from the many altar-slabs which remain, was a long and fairly broad stone table: it was usually less than three feet high, and was covered by a cloth and frontal. It is probable that the frontal, like the vestments of the clergy, followed, in the ordinary parish church, no very strict sequence of colour according to the seasons. For festivals the handsomest and newest frontal and vestments would probably be used. The altar was kept fairly low, to make room for the reredos, which extended across the east wall above the altar, and below the sill of the east window. It will be found that modern restorers, in nine cases out of ten, have disregarded old English uses, by raising an altar until its upper surface is close to the sill of the window, and then by blocking up part, or even the whole of the window, by reredoses or altar screens of stone or wood. High reredoses and altar screens were not unknown, of course, in England; but the ordinary reredos was a single or double band of carving below the east window, as at Geddington or Ludlow. At Stanion in Northants, the string-courses of the east walls of the chancel and north chapel are raised, below the east windows, to form frames for mural paintings or carved retables above the altar. Sculptured tablets were not rare, and indications of their presence may be traced: in the fourteenth and fifteenth centuries, the alabaster, dug out of the Chellaston 'plaster-pits,' and worked by the 'plasterers' of Nottingham, was used, among other purposes, for such tablets. On the north and south sides of the reredos the altar was enclosed by curtains hung on brass rods projecting from the wall or from upright standards. These curtains, known as riddels, had sockets for candles at the ends of the rods. They appear to be derived from the curtains which hung round the altar canopies of basilican churches, and were drawn at the consecration of the elements. Probably the reredos, in most churches, was formed by a painted cloth--that is, a piece of embroidered tapestry--hung behind the altar, or stretched from the upright of the one to the upright of the other riddel. It may be added that the arrangement of cross, candles and flower vases on a shelf, or even on several shelves, at the back of the altar, with which we are so familiar, was not frequent in the middle ages. The cross was usually the central carved or embroidered feature of the reredos: one or two lighted candles were placed upon the altar at mass; and flowers and sweet smelling herbs would be strewn at certain seasons on the chancel floor. Richness of colour and simplicity of furniture were the distinguishing features of the medieval altar. There is a curious ledge upon the back part of the upper surface of the crypt altar at Grantham: it actually lies _upon_ the altar, and its height, as contrasted with that of the modern gradine or shelf, affords the same contrast that