Christianity special veneration was paid to the Mother of God, which in the language of theology is called hyperdulia, to distinguish the honour rendered to her from that given to the other saints. It is not strange, therefore, that after the main or principal altar, the most prominent is that dedicated in a special manner to the Mother of God; and to indicate this specific preference, this altar is usually placed in the most prominent position in the church, i.e. at the right (gospel) side of the main altar. In general it signifies any altar of which the Blessed Virgin is the titular.
Altar-Piece.—A picture of some sacred subject painted on the wall or suspended in a frame behind the altar, or a group of statuary on the altar. In the Middle Ages, instead of a picture or group, the altar-piece consisted in some churches of embossed silver or gold and enamelled work set with jewels. Sometimes the piece was set on the altar itself. If the altar stood free in the choir, and the altar-piece was to be seen from behind as well as from before, both sides were covered with painting (Norton, Church Building in the Middle Ages). The decorated screen, retable or reredos is also called an altarpiece. (See Altar-Screen.)
Altar-Protector.—A cover made of cloth, baize or velvet which is placed on the table of the altar, during the time in which the sacred functions do not take place. Its purpose is to prevent the altar-cloth from being stained or soiled. It should be a little wider than the table and some what longer than the latter, so that it may hang down several inches on each side and in front. It may be of any colour (green or red would seem to be the preferred colours), and its front and side edges are usually scalloped, embroidered, or ornamented with fringes. During the divine services it is removed (Cong. Sac. Rit., 2 June, 1883), except at Vespers, when, during the incensing of the altar at the Magnificat, only the front part of the table need be uncovered, and it is then simply turned back on the table of the altar. It is called the vesperale, the stragulum or altar-cover. It need not be blessed.
Altar-Rail.—The railing which guards the sanctuary and separates the latter from the body of the church. It is also called the communion-rail as the faithful kneel at it when receiving Holy Communion. It is made of carved wood, metal, marble, or other precious material; it should be about two feet six inches high, and on the upper part from six to nine inches wide. The "Rituale Romanum" (tit. iv, cap. ii, n. I) prescribes that a clean white cloth be extended before those who receive Holy Communion. This cloth is to be of fine linen, as it is solely intended as a sort of corporal to receive the particles which may by chance fall from the hands of the priest. It is usually fastened on the sanctuary side and when in use is drawn over the top of the rail. It should extend the full length of the rail, and be about two feet wide, so that the communicant, taking it in both hands, may hold it under his chin. Its very purpose suggests that it is not to be made of lace or netting, although there is nothing to forbid its having a border of fine lace or embroidery. Instead of this cloth a gilt paten, larger than the paten used at the altar, to which a handle may be attached, or a small gilt or silver salver, or a pall, larger than the chalice pall, may be used. These latter are usually passed from one communicant to the other, and when the last at the end of the rail at the Gospel side has received Holy Communion the altar boy carries the paten to the first communicants at the Epistle side. A consecrated paten may never be placed for this purpose in the hands of lay persons.
Altar-Screen.—The Cærem. Episc (I, xii, n. 13) says that if the High Altar is attached to the wall (or is not more than three feet from the wall) a more precious cloth, on which images of Our Lord, of the Blessed Virgin, or of saints, are represented, may be suspended above the altar, unless such images are painted on the wall. This piece of embroidered needlework, cloth of gold, or tapestry is called the altar screen. It is as wide as the altar, and sometimes even extends along the sides of the altar. Its purpose seems to be to separate the altar from the rest of the sanctuary, and to attract to the altar the eyes of those who enter the church. It is called the Dossel or dorsal, from the French dossier, and signifies a back panel covered with stuff. Formerly the stuff corresponded in colour with the other ornaments of the altar and was changed according to the festivals. Instead of the cloth a permanent or movable structure was sometimes raised above the altar at the back. If permanent it consisted of three distinct parts, the base which was as long as the table and the steps of the altar, and reached to the height of the altar table; above this came the panel which formed a decorative frame to a picture, bas-relief, or statue, and the cornice, consisting of a frieze and pediment surmounted by a cross. In the eleventh century the structure was usually made of metal, in the thirteenth century of stone, and from the fourteenth century of wood. Sometimes a folding door was attached which covered the picture during the year, and was opened on grand festivals to expose the picture. If it was a movable structure, it was made of hammered silver or other precious material, supported on the altar itself. The face of this structure which looks towards the nave of the church is called the "retable", and the reverse is called the "counter-retable". This decoration of the altar was not known before the twelfth century. It should always correspond to the architecture or style of the church. The best models are found in the churches of St. Sylvester in Capite, Sta. Maria del Popolo, della Pace and sopra Minerva, at Rome. When this structure is ornamented with panels and enriched with niches, statues, buttresses, and other decorations, which are often painted with brilliant colours, it is called a "reredos". Sometimes the reredos extends across the whole breadth of the church, and is carried nearly up to the ceiling. This decorative screen, retable, or reredos is also called the altar-piece.
Altar-Side.—That part of the altar which faced the congregation, in contradistinction to the side at which the priest stood when formerly the latter stood at the altar facing the people. In ceremonials we frequently find mention of the right and left side of the altar. Before 1488, the epistle side was called the right side of the altar, and the gospel side the left. In that year, Augustine Patrizi, Bishop of Pienza, published a ceremonial in which the epistle side is called the left of the altar, and the gospel side the right, the denomination being taken from the facing of the cross, the principal ornament of the altar, not of the priest or the laity. This change of expression was accepted by St. Pius V and introduced into the rubrics.
Altar-Steps.—In the beginning altars were not erected on steps. Those in the catacombs were constructed on the pavement, and in churches they were usually erected over the confession, or spot where the remains of martyrs were deposited. In the fourth century the altar was supported by one step above the floor of the sanctuary. At present the number of steps leading up to the high altar is for symbolical reasons uneven; usually three, five, or seven, including the upper platform (predella). These steps are to pass around the altar on three sides. They may be of wood, stone, or bricks, but St. Charles (Instructions on Ecclesiastical Building, xi, § 2) would have the two or four lower steps of stone or bricks, whilst he prescribes that the predella, on which the celebrant
