Altar (Lat. altare, from altus, 'high'), the place whereon offerings were laid both by Jews and heathens. The first on record is that which Noah built on leaving the ark. The Israelites, after the giving of the Law, were commanded to make one. Both in the Jewish tabernacle and temple there were two altars, one for sacrifices, and another for incense. The Jewish and oriental altars were generally either square or oblong; those of Greece and Rome, on the other hand, were often round. Sacrifices were offered to the infernal gods, not on altars, but in cavities dug in the ground (see SACRIFICE).
The word has been transferred into the Christian system. For upwards of five centuries, altars in the Christian churches were for the most part made of wood, and an altar of this kind is still to be seen in St John Lateran's at Rome. But the custom of celebrating the liturgical service on the marble sepulchre of the martyrs in the catacombs, led to the introduction of stone altars; and in a council held at Epone in France, 509 A.D., it was decreed that none should be consecrated with chrism except those built of stone. In the Roman Catholic Church, the rubrics require that all altars should be of stone, but the stone itself may be only large enough to hold the host and chalice, and the slab, perhaps no more than a foot square, may rest on, or be inserted in, a board of wood. Such a stone may with license be used as a 'portable altar' by priests requiring to say mass on a journey or in private houses. The stone must in all cases be provided with relics inclosed within it, and be consecrated by a bishop. The altar must be covered with three cloths, one of which must reach to the ground. It should also, if possible, have attached to it in front a 'pallium,' or frontal, varying in removed. The crucifix must stand upon or above the altar, between two candles. The missal is moved from side to side of the altar at various parts of the mass. The epistle is read from the right side, and the gospel from the left; hence it is customary to speak of the epistle and gospel sides of the altar. The Credence Table (q.v.) and the Piscina (q.v.) are adjuncts of an altar.
In the first ages of Christianity, there was only one altar in a church; but, from a very early time, the Latins have used more than one. The principal altar is called the high altar. In the 12th century, the adorning of churches with numerous altars was carried to a great extent, and they were embellished with gold, silver, and precious stones. The Greek Church use but one altar. Altars were frequently placed at the west end of the ancient churches (as in the old British Church), instead of the east. The only perfect altar of the old times in England is the high altar of Arundel church, Sussex. The slab is 12 feet 6 inches long, by 4 feet wide, and 2½ inches thick; the support is of solid stone, quite plain. For 300 years after the time of Christ, the word altar was constantly used to describe the table of the Lord; subsequently 'table' and 'altar' were used indifferently. In the first Prayer-book of King Edward (1549), the word altar was used in the rubric, and the Lord's Supper was still called the Mass; but in 1550, an order was issued for the setting up of tables instead of altars, and in the second Prayer-book of 1552, the word 'altar' was everywhere superseded by 'table:' though 'altar' is retained throughout the coronation service. The table was further ordered to be of wood, and movable. In Mary's reign the altars were re-erected; but in Queen Elizabeth's, some were riotously pulled down, and injunctions were then issued directing that this should not be done, except under the oversight of the curate and at least one churchwarden. It was charged against Archbishop Laud that he had converted communion-tables into altars. What he really did was to remove the tables out of the body of the church, and place them 'altarwise'—i.e. north and south, at the upper end of the chancels, where the altars formerly stood; and a dog having on one occasion run away with a piece of the consecrated bread, he directed that rails should be erected to prevent such desecration in future. By the judgment in the Arches Court, 1845, in the case of Faulkner v. Litchfield, it was decided that altars may not be erected in churches. This case arose out of the erection, by the Cambridge Camden Society, of a stone altar in the Church of the Holy Sepulchre in that town; but it may be questioned whether this judgment has not been virtually modified by the subsequent action of the English Church, and the indirect effect of the judgments of the same court, and of the privy council in the case of Sheppard v. Bennet in 1870–1.
Bowing towards the altar is an ancient practice of the church, a mark of 'homage offered to the seat of the presence of Christ in Holy Communion. Among Roman Catholics, it is the custom to genuflect before the altar when the host is reserved in the Tabernacle (q.v.).
The doctrine of Sacrifice is fully discussed under that head. See LIGHTS (USE OF), BALDACHIN, HIGH PLACES.