Altare Summum
The high altar is so
called from the fact that it is the chief altar in a church, and also
because it is raised on an elevated plane in the sanctuary, where it
may be seen simultaneously by all the faithful in the body of the
church. It symbolizes Christ, and it serves at the same time as the
banquet table on which He offers Himself through the hands of the
priest to the Eternal Father; for Christ is present in our churches not
only in a spiritual manner but really, truly, and substantially as the
victim of a sacrifice. A sacrifice necessarily supposes a priest and an
altar, and the Acts of the Apostles (ii, 42) plainly indicate that the
faithful are to participate in the prayers of the sacrifice and to
partake of the victim. Naturally the altar and priest were separated
from the faithful, who, as St. Athanasius (Quaest. ad Antioch., 37) and
Clement of Alexandria (Strom., vii, 7) inform us, were instructed by
the Apostles to pray, according to the traditions of the Mosaic Law,
facing the East. Hence in the early days of the Church the altar was
usually placed in a chapel at the head of the edifice, the back of
which, whatever may have been the character of the building, looked
directly towards the East, in such a way that it could be seen from any
part by the faithful. When it was impossible to erect a church in such
a manner the altar was located opposite the chief doorway.
In
olden times there was but one altar in a church. The Christian Fathers
speak of one altar only, and St. Ignatius (Ep. ad Philadelph., 5)
refers to this practice when he says: "One altar, as there is one
bishop" (Unum altare omni Ecclesiae et unus Episcopus). This altar was
erected in the middle of the sanctuary between the bishop's throne,
which stood in the apse, and the communion-rail, which separated the
sanctuary from the body of the church. On it Divine services were
celebrated by the bishop only, assisted by the clergy, who received
Holy Communion from his hands. Although each church had but one altar,
there were oratories erected near or around the church in which Mass
was celebrated. This custom is still maintained throughout the East, so
that the liturgical or high altar of the solemn sacrifice is isolated
from what may be called the altars of devotional sacrifice on which
Mass is said privately. Later on, in the time of St. Ambrose (fourth
century), we find the custom of having more than one altar in a church;
and St. Gregory (sixth century) evidently approves of the same by
sending to Palladius, Bishop of Saintes, France, relics for four altars
which, of the thirteen erected in his church, had remained
unconsecrated for want of relics. After the introduction of private
Masses the necessity of several or even many altars in each church
arose. They were erected near the principal altar or in side chapels.
The altar in the sanctuary or high chapel always remained the principal
one of the church, and the pontifical services in cathedrals as well as
the solemn functions in other churches invariably took place at the
chief altar on Sundays, holidays, and other solemn occasions of the
year.

When the custom of erecting the episcopal throne on
the gospel side of the sanctuary became prevalent, the high altar was
removed nearer to the wall of the apse. The object of this was that
sufficient space might be allowed between the lowest step of the altar
and the communion-rail (six to twelve feet) for the proper carrying out
of the ceremonial, and for the accommodation of the clergy who
frequently assisted in large numbers at the solemn celebration of Mass
and of the Divine Offices. The high altar was erected on steps, which
for symbolical reasons were usually of an uneven number -- three or
five, including the upper platform (predella) and the pavement of the
sanctuary, thus placing it on a higher level than the body of the
church, a practice which is still maintained in our churches. In parish
churches the Most Blessed Sacrament is regularly kept on the high
altar, which accordingly should have a tabernacle for the reservation
of the Sacred Species (S.R.C., 28 Nov., 1594; 21 Aug., 1863). The
prescribed ornaments are a crucifix and six high candlesticks. The high
altar in a church that is to be consecrated should be a fixed altar
(see ALTAR, FORM OF), which according to the prescriptions of the Roman
Pontifical (h.l.) is itself to be consecrated simultaneously with the
solemn dedication of the church edifice. Hence it must stand free on
all sides, allowing ample room for the consecrator to move around it.
As its name indicates, the high altar, being the chief place for the
enactment of the sacrificial function, is to be prominent not only by
its position but also by the richness of its material and
ornamentation. Apart from the liturgical part of the Mass, it serves as
the repository for the Eucharistic Presence and becomes the centre of
all the more solemn parochial functions of the year.[1]