Religion has always been the patron of architecture. Wherever civilized skill has been found it has been present to claim the noblest employment of the high gift for its own purposes, The heathen nations have felt its mighty and creative impulse. Imbued with the feeling that they should build more grandly for their gods than for themselves, they have made the most lavish expenditures upon sacred edifices.

Christianity, with her powerful sway over the minds and hearts of men, was naturally quite the equal of preceding systems in subsidizing skill and treasure for religious buildings. No sooner were the needful resources at her command than she began to employ them with Solomonic munificence. A large proportion of the wealth of society flowed to the sanctuary. Europe had scarcely been evangelized before it was dotted with costly and stately structures. A town might be destitute of every other token of elegance, its inhabitants might be compelled to live in wooden buildings of the most humble description; but it was almost certain to have its church built of stone, generously adorned, and towering in grandeur far above all surrounding structures.

In the history of Christian architecture, we may note several eras, or the successive appearance of several different types, each of which has been dominant for a time. It should be understood, however, that in no case have the earlier styles been wholly displaced by the later. Different types have co-existed, and in many cases have worked upon and modified each other. Still there are lines of demarkation which may be traced with sufficient definiteness. Most writers, while perhaps they indulge some difference in terminology, distinguish five styles as successively appearing before the Reformation. In a not unusual classification these are specified as follows: the Basilica, the Byzantine, the Romanesque, the Gothic, and the Renaissance.

1 Fergusson uses a different terminology, giving the name of Romanesque to the first style, and calling the third Early or Round-arch Gothic. Lord Lindsay describes the third under the title Lombard style.

For about two centuries the Christians probably accomplished very little in the way of church building. The private dwelling oftentimes served as the sanctuary. For regular houses of worship there was no adequate security during the era of persecutions. Still the Christians by no means waited for heathen fury to deal its final blows before providing themselves with edifices devoted specially to religious services. Whatever may have been the number of such edifices at an earlier date, it is certain that many were built in the last half of the third century.

The opinion has been very generally entertained that the Roman basilica, or hall of justice, was the model which the Christians followed in their early architectural efforts; but recently opposing theories have been broached. Reference has been made to the influence of the Jewish synagogue. Some writers have contended that the banqueting hall of the private dwelling, which among the wealthy was spacious and elegant, afforded the main features, of the plan adopted. Some have regarded the schola, or hall of a fraternity, used mainly if not exclusively for funeral rites, as the most effective model in the first stages of Christian architecture. Such elements as these in the building art of the time were doubtless objects of continued observation. There is no good reason, therefore, why any one of them may not be supposed to have exerted a measure of influence.

1 Prof. C. W. Bennett, after a careful survey of the subject, fixes upon an eclectic theory in these terms: "The ordinary private dwelling-house, the triclinia of the more elegant houses of the nobler families that had embraced Christianity, the lodge-rooms, the cellæ of the burial chapels, and the imposing interior arrangement of colonnades in the heathen law-basilicas, are the sources whence are derived the germs which under the fostering and inspiring spirit of the new religion during periods of toleration and peace were developed into a distinctively Christian architecture whose chief characteristics continued for a thousand years."
(Christian Archæology, pp. 183, 184.)

Still, it is proper to consider the basilica a very influential factor, as being the most conspicuous example at hand of a spacious columned hall. It was an oblong building with a gallery on either side supported by a row of columns. The galleries were roofed over. The middle space in some instances was open to the sky, but in others it was roofed. In the latter case it readily supplied the plan of a building suited to the uses of a Christian assembly.

On appropriating the basilican type the Christians divided and arranged the interior space according to the demands of their liturgical and ecclesiastical system. The apse and the adjoining portion were separated from the rest of the church and raised somewhat above the general level. This section, which was the place of ecclesiastics, was called the sanctuarium or presbyterium. The raised seat of the bishop was at the centre of the apse; the higher clergy were ranged on either side near the wall. The altar was placed to the front of the apse. Originally it was uncovered, but afterwards was surmounted by a tabernacle resting on pillars, the so-called ciborium. The lower clergy, who took part in the choir-singing, occupied a space which was railed off in the body of the house in front of the presbyterium. On either side of this space, which from its occupants took the name of the "choir," was a pulpit. From the one on the left (or north) the Gospel was read; from the one on the right, the Epistle. In time, however, the choir was located within the presbyterium, and the pulpits were attached to the barrier which separated the presbyterium from the rest of the building. The juncture of the transept with the nave was often made by a large arch called the triumphal arch. Underneath the presbyterium, sometimes partly below the level of the earth, was the crypt, in which the relics of the saints were deposited.

The nave, or central aisle, which was carried considerably higher than the side aisles, was separated from the latter by rows of columns usually surmounted by round arches. In a majority of instances there was only one aisle on each side of the nave, but a number of the early churches, as St. Peter's, St. Paul's, and the Lateran, had two aisles on each side.

At the entrance end, which commonly, though not always in the earlier stage, lay to the West a narrow space, or vestibule, was divided off, called the narthex. This was appointed to the catechumens and to that class of penitents who were permitted to hear the Scripture lessons and the sermon but were dismissed before the celebration of the Eucharist.

In front of the church was usually an atrium or forecourt, having a fountain or laver in the centre at which the worshiper might sprinkle himself, before entering, in token of purification. During the progress of divine service the excommunicate were not expected to approach nearer than this court.

Adjacent to the rectangular basilica as "a ceremonial or sacramental adjunct," there was commonly a round or octagonal edifice, used for baptism and for funereal rites. The former use has given the name to the edifice. It was several centuries before the font was brought into the church proper and the custom of building separate baptisteries was discontinued.

The early Christian basilicas generally presented very plain exteriors. They were without towers; indeed it is not certain that towers were built in connection with churches before the seventh or eighth century, and then for a while they were merely adjacent structures designed to serve as belfries, not integral parts of the church edifice. Interior ornamentation, on the other hand, was far from being neglected. Not to speak of the fine array of columns taken very generally from classic remains, there was in many of the churches a generous display of the precious metals, of mosaic-work, and of fresco. Mosaic was especially abundant, as in this era there was relatively much greater skill in this style of ornamentation than in painting proper. The semi-dome of the apse was sometimes covered with it, and it also found place on the walls of the nave. A device of Byzantine artists in forming a background of gold-leaf under plates of transparent glass provided for it a very brilliant appearance. In delicacy of expression this mosaic-work was doubtless inferior to painting, but a large compensation for this lack was offered in its superior durability. While four centuries or less have seriously dimmed the glory of the great masterpieces of Christian painting, the pictures of the Byzantine artists are said to be as fresh and brilliant to-day as they were when first executed, more than a thousand years ago.

Ruins of churches in North Africa and Egypt have been discovered which are supposed to antedate the reign of Constantine. Distinguishing characteristics are their small size, the absence of transepts, and in some cases such a construction of the apse that it appears only on the interior. Notwithstanding their limited dimensions some of these churches have five aisles. Remains of churches which were presumably of early date are also found in Syria and Asia Minor.

In the central parts of the empire the oldest churches of which we have historic notice date from the time of Constantine. In both East and West they were of the basilican type. Chief among these was St. Peter's of Rome, built near the circus of Nero in the place where the apostle was reputed to have suffered martyrdom. It was founded by Constantine, and continued, though not without some alterations, till the latter part of the fifteenth century, when the slowly executed design of the present structure was entered upon. Though greatly surpassed by the later edifice in size and magnificence, the original St. Peter's was a noble basilica, rich in ornamentation, and excelling in dimensions most of the later cathedrals, being three hundred and eighty feet long by two hundred and twelve feet in width. The Lateran Church (S. Giovanni in Lateran) was another of the basilicas which Rome owed to the good offices of Constantine. It was fitted up on the site of the Lateran palace which the Emperor donated to the Roman bishop. The building of S. Croce and of S. Pudenziana is also attributed to Constantine. St. Paul's (S. Paolo fuori le mura), a short distance from the walls of Rome, was built in the closing part of the fourth century. It ranks among the grandest specimen of the early basilica. In some points it excelled the original St. Peter's. Its columns bore a better proportion to the height of the building and its transept had also a more appropriate width, being the same as that of the nave. The interior arrangement as a whole was such as to give a very fine effect. The modern St. Paul's, on the same site, was designed to reproduce the general style of the original one, which was burned in 1823. Among the existing churches of Rome or its neighborhood the S. Clemente is mentioned as specially adapted to furnish a good idea of the primitive basilica. The S. Maria Maggiore, the S. Lorenzo, and the S. Pudenziana subserve a like purpose.

Ravenna almost rivalled Rome as a theatre of early Christian architecture. It still presents an interesting field of study. The five-aisled cathedral, built in the early part of the fifth century, no longer exists; but its baptistery has been preserved together with its original decorations. One finds here also the noble basilicas S. Apollinare in Nuovo and S. Apollinare in Classe, - the former founded by Theodoric, the latter (situated about three miles from the walls) built in the time of Justinian. These churches differed in some respects from the early Roman. They were without transepts and were more consistent and uniform in appearance, inasmuch as the columns with which they were furnished were made to order, instead of being borrowed from classic remains.

In the Byzantine style, which came in as rival to the basilica, the main feature was the dome. This was made the centre toward which the whole structure converged. An oblong form being opposed to the focalizing of the interest in the dome, the ground plan which had been prevalent in the basilica was changed. The square enclosure, or the Greek cross, which with its short and equal arms approximates to a square, was substituted for the oblong form of the Latin cross. About the central dome in many cases were smaller domes.

This style was not altogether a new invention. Before the beginning of Christian architecture the pantheon had already supplied an example of the dome. But in the pantheon the dome rested upon a circular wall, while in the Byzantine churches it rested upon pillars or pillar-masses, -- an arrangement adding greatly to the soaring, upreaching aspect of the edifice. To whatever extent, then, it may have been suggested by previous architecture, the Byzantine exhibited a daring advance.

The beginning of this style may be placed in the fifth century. In the sixth century the St. Sophia of Constantinople presented to the world the most admirable specimen of the Byzantine proper. It was built under the patronage of Justinian. The first dedication occurred in 537. Twenty years afterwards an earthquake caused the collapse of a part of the dome. The church, however, was ready for rededication in 563, and from that date has remained unchanged in its leading features. The edifice exclusive of its adjuncts covers an area two hundred and fifty feet long by two hundred and twenty-eight feet broad. The dome has a curvature something less than that of a hemisphere, being one hundred and seven feet across by forty-six feet in height. Forty windows at its base afford abundant light. The summit of the dome is not less than one hundred and seventy feet above the pavement, and full effect is given to this great altitude by the arrangement of the adjacent spaces. "The eye wanders upwards from the large arcades of the ground floor to the smaller arches of the galleries, and thence to the smaller semi-domes. These lead the eye on to the larger, and the whole culminates in the great central roof. Nothing probably so artistic has been done on the same scale before or since." Fergusson, Pt. II. Bk. ix. Chap. III.

On the exterior the St. Sophia presented a plain appearance. Some suppose that here the design was left incomplete, it having been the intention of the founder that marble facing and other ornamentation should be added. The interior, on the other hand, was marvelously rich. The altar was a mass of costly stones and precious metals. The pillars were of porphyry, verd antique, or marbles of the finest quality. The walls, the domes, the roofs, were lavishly adorned. The effect of the whole before yet the hand of the Mohammedan victor had defaced any part must have been well-nigh beyond competition.

"When we consider," says Sir Gilbert Scott, "the whole as clothed with the richest beauties of surface, its piers encrusted with inlaid marbles of every hue, its arcades of marble gorgeously carved, its domes and vaultings resplendent with gold mosaic interspersed with solemn figures, and its wide-spreading floors, rich with marble tessellation, over which the buoyant dome floats, self-supported, and seems to sail over you as you move, --I cannot conceive of anything more astonishing, more solemn, and more significant. Well might its imperial founder exclaim, when with pardonable exultation he viewed the result of his costly aspirations, 'Glory to God, who hath thought me worthy to accomplish so great a work. I have vanquished thee, O Solomon !'" 1 Lectures on Mediæval Architecture, Vol. II.

The estimate of Fergusson is not less appreciative.

"Turn it as we will," he says, "and compare it as we may with other buildings of its class, the verdict seems inevitable that Sta. Sophia -- internally at least, for we may omit the consideration of the exterior as unfinished -- is the most perfect and beautiful church which has yet been erected by any Christian people."

The Byzantine continued to be the model for the Eastern Church.

2 Still it was not followed exclusively in all regions. The Coptic Churches in Egypt present a mixture of the Basilican and the Byzantine types (A. J. Butler, The Ancient Coptic Churches of Egypt).

On western soil it also exercised a marked influence as a modifying factor and found besides some specific embodiments. The church of S. Vitale in Ravenna and the chapel of Charlemagne at Aix la Chapelle were of the Byzantine order. St. Mark's in Venice, however, presents the most renowned western specimen of this style. To be sure, St. Mark's in its composite character embraces other elements, but the Byzantine so preponderate that it is most fitly ranked under this name. It was built mainly between 976 and 1071. The foundation plan is the Greek cross, the interior length being two hundred and twenty-eight feet and the breadth two hundred and ten feet. The roof is surmounted by five domes, one over the centre and one over each arm of the cross. Five hundred columns, in varied styles, enter into the ornamentation, interior and exterior. The mosaics are said to cover an area of more than forty-five thousand square feet, and there is besides a profusion of ornaments in the way of gilding, bronze, and Oriental marble. The result is an appearance of amazing richness. In the view of some critics ornamentation has been carried to the border of the fantastic. Others, however, have not hesitated to pronounce St. Mark's the most perfect piece of color harmony in the world.