The Mass is a sacrifice, and, being a sacrifice, must be offered on an altar by a priest. "Altar" means something elevated, from the Latin word "altus," high. The first altar was the wooden table at which our Lord celebrated the Last Supper, and in the first ages of the Church wooden tallies served usually for altars. As we saw in No. 63, in Rome, during the persecutions, the Mass was said in the Catacombs or in the Memorials of the Martyrs. The priest used the tomb as an altar, and those tombs were of stone, and usually shaped like an oblong box. When the persecutions ceased, and the great churches were built over the memorials, or the remains of the martyrs were transported to other places, this custom was retained. The altar was built in the shape of a stone tomb over or around the relics of the martyrs. The altars which were erected over the relics took the form of a flat stone supported by pillars or by vertical slabs, between which lay the bodies of the martyrs. The altars in which the relics were enclosed were constructed like ordinary box-tombs.
The stone altar is now the rule in our Liturgy. It is not always possible, however, to have such altars, and, if we examine the majority of altars, we find them of wood. This wooden structure, however, is only a framework. A closer examination would reveal the fact that in the center of the wooden table a piece of stone is inserted. This is the real altar. In it there is a receptacle which contains the relics of some saints, so that it is really a tomb and a stone tomb. These small altars are called "Altar Stones," and Mass must not be offered except on them or on regular stone altars.
As we saw in No. 67, the priest faced the East during the celebration of Mass. In churches whose sanctuary was situated in the East he therefore stood between the people and the altar. There are, however, in Rome certain Basilicas, like Saint John Lateran, where the sanctuary is in the West. In such churches the priest still faced the East, and the altar was between him and the people. This style of standing has not spread outside of Rome, as it is taken for granted that all churches are properly orientated. From this we see that the altar stood isolated in the sanctuary and somewhat near the chancel railings. Behind it and in the center of the rear wall of the sanctuary was the Bishop's seat, and to the right and left, generally in a semi-circle, were the seats for the ministers. In course of time the altar was moved farther back, and the Bishop's seat was changed to the North side, so that in some churches the altar is built against the sanctuary wall. In the Apocalypse Saint John saw the vision of heaven under the appearance of a Christian church of his time:
"Straightway I was in the Spirit: and behold there was a throne set in heaven and one sitting upon the throne. And round about the throne were four and twenty thrones: and upon the thrones I saw four and twenty priests sitting, arrayed in white garments; and on their heads crowns of gold. And there were seven lamps of fire burning before the throne which are the seven spirits of God. And I saw in the midst of the priests a Lamb standing as though it had been slain." (Chapter 4)
The use of the umbrella as a sign of honor is of the highest antiquity, and is still known in oriental countries. In the West it takes the shape of a canopy, or hanging, which we find in our courts of justice over the judge's seat. The Church also employed it, and the projecting work over the Bishop's throne, statues of saints, baptismal fonts, and the silken canopy used when the Blessed Sacrament is carried in procession, are all derived from the umbrella. The same mark of honor was erected over the altar. It usually consisted of four or six pillars supporting a richly decorated roof. Four curtains were draped between the pillars, and, when drawn, cut off the view of the altar from the people. The rich stuff of which these curtains were made came from "Baldac," now Bagdad, and thus the structure itself was called a "Baldachino". Why it is called "Ciborium" is not known. The Baldachino is supposed to be in all churches, but is found very seldom in America. In many places a vestige of it appears in the pillars placed on both sides of the altar, against the wall and supporting a kind of arch.
A small Table or a niche in the sanctuary wall on the south side of the altar is known as the credence. It contains the vessels and other necessaries for the Sacrifice. These are not taken to the altar until it is time to use them in the service. This table is known as the "Credence," from a custom in vogue during the early ages. The meats which were to be used at the tables of princes were first placed on a sideboard and tasted by a steward. The object of the custom was to guard against the serving of viands not properly cooked, as well as to provide against secret enemies who had recourse to poison to revenge personal or political wrongs. When the meat had been tasted it was worthy of trust or "credence." The table itself soon obtained this name, and the word passed into common and Church use with the meaning of sideboard.
As we have seen, the sanctuary was shut off from the nave by railings. Those railings were sometimes very high in order to protect the relics of the saints which were in the sanctuary. With us the railings now serve as a Communion table, which formerly was a separate piece of furniture. They are provided with a top more or less flat, to which is often attached a white cloth used when the people approach to receive Holy Communion.
The preaching of the word of God forms part of the Church service. In the beginning the Bishop preached from his chair, which was placed at the end of the sanctuary. Near the chancel rails, however, in the front of the sanctuary, were two raised structures called "Ambos." The term comes from a Greek word meaning "to go up." From the Ambos were read the lessons from Holy Scriptures, and at times the preacher spoke from them. The picture of the Ambo in the Basilica of Saint Clement, at Rome, gives an idea of their construction. Now, in some of the Basilicas pillars sprang from the chancel rails and carried an arch or beam bearing an image of Christ rising from the dead, or a Crucifix. This is known as the triumphal arch. Together with the chancel railing, it made a complete separation between the nave and sanctuary. In the Greek church chancel rails and triumphal arch have grown into a partition which entirely shuts off the altar from the people. It is decorated with statues and paintings, and is called the Iconostasis or "image stand." Now, as the triumphal arch and the chancel rails grew together to form a partition, so an other partition was created by the joining of the triumphal arch and the Ambo. In the great cathedral and monastic churches the divine services were performed by large choirs. In order to accommodate those choirs, stalls were built outside the sanctuary in the transept. At the end of the stalls, toward the nave, the Ambos were placed, with a railing separating them from the people, and sometimes the triumphal arch was there. In the fourteenth century we find that these three features were embodied in a great gallery constructed sometimes of wood and sometimes of stone and marble, and cutting off the choir from the body of the church. Winding staircases from the north and south sides led to the top of the gallery, whereon were placed the reading desks of the old Ambos. Over the entrance was erected the Cross, and hence the whole structure was known as the "Rood Loft," Rood being an old English word for Cross. The bird s-eye view of the old choir in the Cathedral of Paris shows all the details. Those great galleries, however, were very inconvenient in this, that they shut off the view of the altar from the people. Accordingly, we find that their use was not very extensive, and that in many places they were removed to the west end of the church, and correspond with our organ gallery. If in the picture of the choir of the Cathedral of Paris we remove all of the rood-loft except the winding stair case, we get our modern "pulpit," the successor of the ancient "ambo." Besides those stationary pulpits, movable pulpits are also used. Before the Reformation there were outdoor pulpits; but outdoor preaching ceased on account of the religious disturbances of the sixteenth century.
- taken from The Mass, by Father Peter Christopher Yorke