The simplest form of a church is that of an oblong room. At one end is the entrance and at the other a raised floor or platform. This platform is separated from the body of the church by rails. From the Latin name "cancelli," this part is sometimes called the "chancel." It contains the altar whereon the sacrifice is offered and the seats for the priests and other ministers. The body of the church is reserved for the people, and a porch or vestibule separates it from the entrance.
It was a rule that all churches should face the East. Christ is called the Orient or the Day Spring from on high, and men looked to the East when they thought of Him coming on the altar. Hence the West front of the church would be the entrance, and the Chancel would be situated at the East end. For many reasons, this rule of "Orientation," or of turning the church towards the East, is more honored in the breach than the observance, but in liturgical language that portion of the church which contains the altar is still called the East, no matter what point of the compass it may in reality face. The other sides of the church are named accordingly. Thus, the chief entrance is in the West end, the left hand facing the altar is the North, and the right hand the South.
The original plan was often enlarged by building an addition at right angles to the North and South sides, so that the ground plan was in the form of a cross. Such churches are called Cruciform churches, and are very common. These additions are known as the North and South "transepts" from a Latin word, "Transeptum," which means an enclosure across. The transepts might be so added as to form a Greek or Latin cross. The Greek cross has all the arms of equal length; the Latin cross has the stem longer than the cross piece. Churches of other shapes are found occasionally, as round, square and semi-circular; but the cruciform shape has always been the most popular.
Catholic Worship is a public act performed by public officers. The central point of Catholic Worship is the Sacrifice which is offered by priests, who share in the priesthood of Jesus Christ, and act in His name. They are His representatives, and, like Him, they stand between God and the people. In that Sacrifice Christ comes personally into the midst of the worshipers, and is truly present upon the altar. In the Old Testament we find that God commanded Moses to divide the Tabernacle into two parts. In one of those parts, called the Holy of Holies, was placed the Ark of the Covenant. Upon the Ark was a covering of pure gold, over which the cherubim spread their wings. This was known as the Mercy Seat or Propitiatory, and was the place where God became present to Moses.
"Thou shalt put the Mercy Seat above upon the Ark, and in the Ark thou shalt put the testimony that I shall give thee. And there I will meet with thee, and I will speak with thee from above the Mercy Seat, from between the two cherubim which are on the ark of the testimony, all things which I shall command thee concerning the children of Israel." - Exodus 25
In the New Testament the altar on which Christ is present corresponds to the Mercy Seat. We find, therefore, that it occupies the most prominent place in the church or the chancel. That place is also called the "Sanctuary," from the Latin word "Sanctus," which means holy. It corresponds to the Holy of Holies of the Tabernacle, and no one is allowed to enter it except the priests and the ministers of the Sacrifice. It is separated, as we have said, from the rest of the church by a railing to show that the priests take the place of Jesus Christ and worship in His name for the people. It is also raised by steps above the rest of the church, not only in order that the congregation may be able to see what is doing, but also to signify that the Altar, which signifies Christ, and they who bear the priesthood of Christ, stand like Christ, the one mediator, between God and man. From a Greek word meaning "I ascend," or "go up," the Sanctuary is also called the "Ambo," arid from the fact that the singers had their station therein it is sometimes known as the Choir.
The Sacrifice is offered for the Christian people, and consequently they have a right to assist thereat. Hence, as we have said, the portion of the church outside the sanctuary is given up to them. Either from its resemblance to a ship, or from the fact that in early Christian times the Church was compared to a ship in which the faithful journeyed towards heaven, this part of the building was called the "Nave," from the Latin "Navis," a ship. We have already shown how the church was enlarged by the addition of transepts at right angles to the nave. An earlier method of gaining increased room was to add oblong structures running parallel to the nave and separated from it by pillars. These narrower naves went by the name of "Aisles," from the Latin "ala," a wing. The reason why the church was not simply broadened by erecting the walls of the nave farther apart is found in the desire not to weaken the roof by giving it too wide a span. Sometimes a second set of aisles was added when the first set did not give the desired room. Originally the nave was divided in the center by a railing running from the chancel to the entrance, or east and west. On the right hand, or south side, were the men, and on the left hand, or north side, were the women.
The nave properly belongs to the Christian congregation. It is their station in the Lord's house. But in early times there were many people who did not belong to the congregation, but yet attended church. In the first place, the number of non-Christians who were being instructed in the faith was very large. As they were learning the "Catechism" they were called "Catechumens". Then there were always some who had forfeited their place in the congregation by grave and public sin. Before being restored they were compelled to undergo long years of penance, and not until that penance was performed were they permitted to mingle with the faithful. For the convenience of those two classes there was at the west end of each church a large vestibule or hall, for at certain times in the service, as we saw above, the Catechumens and Penitents were dismissed from the church proper. This hall was also called a "Portico" because in the larger churches it consisted of a pillared cloister surrounding an open space, in which was a fountain. When the practice of public penance fell into disuse, and the extension of Christianity reduced the number of Catechumens, the "vestibule" or "porch" was reduced to its present insignificant dimensions.
The essential portions of the church are the Sanctuary and Nave. In course of time, however, many outbuildings were added for various purposes. As we shall see, the services required much display, both in the matter of vestments for the clergy and furniture for the altar and sanctuary. These "ornaments," as they were technically called, were in the charge of "deacons," who had in early times the management of the property of the church. A structure was built close to the sanctuary, in which the ornaments were preserved. As it was managed by the deacon, it was called the "diaconicum". Now it is known as the "Sacristy," because sacred objects are preserved there; or as the "Vestry," because the clergy put on their vestments there.
The Christians were at first notified of the time of divine services either at a previous meeting or by messengers sent from house to house. After the persecutions, public signals were employed, such as a bugle call or the noise made by striking on a piece of metal or wood. A survival of this usage is to be found in the custom of using wooden "clappers" during the last three days of Holy Week. In the sixth century, "Bells" appear in Ireland, France, and later in Italy. By the end of the seventh century, they were common all over Europe. It was not, however, until the ninth century that they were adopted in the East. To house the bells and to enable their sound to travel to longer distances, "towers" were built for them. Those, like the Round Towers, or Bell Towers, of Ireland, were at first detached from the building. Gradually, however, they were made part of the edifice, as we have them now. "Belfry" is another name for these towers. The derivation of the word is uncertain. There was a French word, "beffroi," which means a tower, and, as towers were used for bells, the first syllable in English was taken for "bell."
In the early ages of the Church it was the general rule that Baptism was administered in the presence of the Bishop twice a year, namely, on the Saturdays before Easter and Pentecost, Hence we find in the neighborhood of cathedrals small churches set apart for this purpose. They were usually round, and often stood in the open court described in No. 71. When by the conversion of Europe the number of Baptisms grew so large that the bishops could no longer perform them, the administration of the Sacrament devolved on their representatives in each community, namely, the Parish Priests. This practice was accompanied by the erection of Baptistries in parish churches. Sometimes one of the towers is used for the purpose, sometimes a side room, and often, where space cannot be had, or where the church is poor, a simple niche or a railed-off enclosure in the nave or aisles serves for a Baptistry.
- taken from The Mass, by Father Peter Christopher Yorke