Altar (Catholicism) - The Form of An Altar

The Form of An Altar

In the primitive times there were two kinds of altars:

• The arcosolium or monumentum arcuatum, which was formed by cutting in the tufa wall of the wider spaces in the catacombs, an arch-like niche, over a grave or sarcophagus. The latter contained the remains of one or several martyrs, and rose about three feet above the floor. On it was placed horizontally a slab of marble, called the mensa, on which Mass was celebrated.
• The altar detached from the wall in the cubicula, or sepulchral chapels surrounded by loculi and arcosolia, used as places of worship in the catacombs or in the churches erected above ground after the time of Constantine. This second kind of altar consisted of a square or oblong slab of stone or marble which rested on columns, one to six in number, or on a structure of masonry in which were enclosed the relics of martyrs. Sometimes two or four slabs of stone were placed vertically under the table, forming a stone chest. In private oratories the table was sometimes made of wood and rested on a wooden support. Within this support were placed the relics of martyrs, and in order to be able to expose them to view, folding doors were fixed on the front.

The Liber Pontificalis states that Pope Felix I decreed that Mass should be celebrated on the tombs of martyrs. This no doubt brought about both a change of form, from that of a simple table to that of a chest or tomb, and the rule that every altar must contain the relics of martyrs. Usually the altar was raised on steps, from which the bishop sometimes preached. Originally it was made in the shape of an ordinary table, but gradually a step was introduced behind it and raised slightly above it. When the tabernacle was introduced the number of these steps was increased. The altar is covered, at least in basilicas and also in large churches, by a canopy supported by columns, called the ciborium, upon which were placed, or from which were suspended, vases, crowns, baskets of silver, as decorations. From the middle of the ciborium, formerly, a gold or silver dove was suspended to serve as a pyx in which the Blessed Sacrament was reserved. Veils or curtains were attached to the columns which supported the ciborium. The altar was often encircled by railings of wood, or metal, called cancelli, or by low walls of marble slabs called tranennae.

According to the present discipline of the Church, there are two kinds of altars, the fixed and the portable. Both these denominations have a twofold meaning, i.e. an altar may be fixed or portable either in a wider sense or in the liturgical meaning. A fixed altar, in a wider sense, is one that is attached to a wall, a floor, or a column whether it be consecrated or not; in the liturgical sense it is a permanent structure of stone, consisting of a consecrated table and support, which must be built on a solid foundation. A portable altar in a wider sense is one that may be carried from one place to another in the liturgical sense it is a consecrated altar-stone, sufficiently large to hold the Sacred Host and the greater part of the base of the chalice. It is inserted in the table of an altar which is not a consecrated fixed altar.

The component parts of a fixed altar in the liturgical sense are the table (mensa), the support (stipes) and the sepulchrum. (See altar cavity.) The table must be a single slab of stone firmly joined by cement to the support, so that the table and support together make one piece. The surface of this table should be perfectly smooth and polished. Five Greek crosses are engraved on its surface, one at each of the four corners, about six inches from both edges. but directly above the support, and one in the centre. The support may be either a solid mass or it may consist of four or more columns. These must be of natural stone, firmly joined to the table. The substructure need not, however, consist of one piece, but should in every case be built on a solid foundation so as to make the structure permanent. The support may have any of the following forms:

• at each corner a column of natural stone, and the spaces between the columns may be filled with any kind of stone, brick, or cement;
• the space between the two columns in front may be left open, so as to place beneath the table (exposed) a reliquary containing the body (or a portion of the body) of a saint;
• besides the four columns, one at each corner, a fifth column may be placed in the centre at the front. In this case the back, and if desired the sides also, may be filled with stone, brick, or cement;
• if the table is small (it should in every case be larger than the stone of a portable altar), four columns are placed under it, one at each corner and, to make up the full length required, frames of stone or other material may be added to each side. these added portions are not consecrated, and hence may be constructed after the ceremony of consecration;
• if the table is deficient in width, four columns are placed under it, one at each corner, and a frame of stone or other material is added to the back. This addition is not consecrated, and may be constructed after the consecration of the altar.

In the last two cases the spaces between the columns may be filled with stone brick, or cement, or they may be left open. In every case the substructure may be a solid mass, or the interior may remain hollow, but this hollow space is not to be used as a closet for storing articles of any kind, even such as belong to the altar. Neither the rubrics nor the Sacred Congregation of Rites prescribe any dimensions for an altar. It ought, however, to be large enough to allow a priest conveniently to celebrate the Holy Sacrifice upon it in such a manner that all the ceremonies can be decorously observed. Hence altars at which solemn services are celebrated require to be of greater dimensions than other altars. From the words of the Pontifical we infer that the high altar must stand free on all sides (Pontifex circuit septies tabulam altaris), but the back part of smaller altars may be built against the wall.