[Ill.u.s.tration: FIG. 66.--STA. COSTANZA, ROME.]

The Christian basilica (see Figs. 67, 68) generally comprised a broad and lofty nave, separated by rows of columns from the single or double side-aisles. The aisles had usually about half the width and height of the nave, and like it were covered with wooden roofs and ceilings. Above the columns which flanked the nave rose the lofty clearstory wall, pierced with windows above the side-aisle roofs and supporting the immense trusses of the roof of the nave. The timbering of the latter was sometimes bare, sometimes concealed by a richly panelled ceiling, carved, gilded, and painted. At the further end of the nave was the sanctuary or apse, with the seats for the clergy on a raised platform, the _bema_, in front of which was the altar. Transepts sometimes expanded to right and left before the altar, under which was the _confessio_ or shrine of the t.i.tular saint or martyr.

An _atrium_ or forecourt surrounded by a covered arcade preceded the basilica proper, the arcade at the front of the church forming a porch or _narthex_, which, however, in some cases existed without the atrium.

The exterior was extremely plain; the interior, on the contrary, was resplendent with incrustations of veined marble and with sumptuous decorations in gla.s.s mosaic (called _opus Grecanic.u.m_) on a blue or golden ground. Especially rich were the half-dome of the apse and the wall-s.p.a.ce surrounding its arch and called the _triumphal arch_; next in decorative importance came the broad band of wall beneath the clearstory windows. Upon these surfaces the mosaic-workers wrought with minute cubes of colored gla.s.s pictures and symbols almost imperishable, in which the glow of color and a certain decorative grandeur of effect in the composition went far to atone for the uncouth drawing. With growing wealth and an increasingly elaborate ritual, the furniture and equipments of the church a.s.sumed greater architectural importance.

A large rectangular s.p.a.ce was retained for the choir in front of the bema, and enclosed by a breast-high parapet of marble, richly inlaid. On either side were the pulpits or _ambones_ for the Gospel and Epistle.

A lofty canopy was built over the altar, the _baldaquin_, supported on four marble columns. A few basilicas were built with side-aisles, in two stories, as in S. Lorenzo and Sta. Agnese. Adjoining the basilica in the earlier examples were the baptistery and the tomb of the saint, circular or polygonal buildings usually; but in later times these were replaced by the font or baptismal chapel in the church and the _confessio_ under the altar.

[Ill.u.s.tration: FIG. 67.--PLAN OF THE BASILICA OF ST. PAUL.]

Of the two Constantinian basilicas in Rome, the one dedicated to +St.

Peter+ was demolished in the fifteenth century; that of +St. John Lateran+ has been so disfigured by modern alterations as to be unrecognizable. The former of the two adjoined the site of the martyrdom of St. Peter in the circus of Caligula and Nero; it was five-aisled, 380 feet in length by 212 feet in width. The nave was 80 feet wide and 100 feet high, and the disproportionately high clearstory wall rested on horizontal architraves carried by columns. The impressive dimensions and simple plan of this structure gave it a majesty worthy of its rank as the first church of Christendom. +St. Paul beyond the Walls+ (S. Paolo fuori le mura), built in 386 by Theodosius, resembled St. Peter's closely in plan (Figs. 67, 68). Destroyed by fire in 1821, it has been rebuilt with almost its pristine splendor, and is, next to the modern St. Peter's and the Pantheon, the most impressive place of worship in Rome. +Santa Maria Maggiore+,[15] though smaller in size, is more interesting because it so largely retains its original aspect, its Renaissance ceiling happily harmonizing with its simple antique lines.

Ionic columns support architraves to carry the clearstory, as in St.

Peter's. In most other examples, St. Paul's included, arches turned from column to column perform this function. The first known case of such use of cla.s.sic columns as arch-bearers was in the palace of Diocletian at Spalato; it also appears in Syrian buildings of the third and fourth centuries A.D.

[Footnote 15: Hereafter the abbreviation S. M. will be generally used instead of the name Santa Maria.]

[Ill.u.s.tration: FIG. 68.--ST. PAUL BEYOND THE WALLS. INTERIOR.]

The basilica remained the model for ecclesiastical architecture in Rome, without noticeable change either of plan or detail, until the time of the Renaissance. All the earlier examples employed columns and capitals taken from ancient ruins, often incongruous and ill-matched in size and order. +San Clemente+ (1084) has retained almost intact its early aspect, its choir-enclosure, baldaquin, and ambones having been well preserved or carefully restored. Other important basilicas are mentioned in the list of monuments on pages 118, 119.

+RAVENNA.+ The fifth and sixth centuries endowed Ravenna with a number of notable buildings which, with the exception of the cathedral, demolished in the last century, have been preserved to our day. Subdued by the Byzantine emperor Justinian in 537, Ravenna became the meeting-ground for Early Christian and Byzantine traditions and the basilican and circular plans are both represented. The two churches dedicated to St. Apollinaris, +S. Apollinare Nuovo+ (520) in the city, and +S. Apollinare in Cla.s.se+ (538) three miles distant from the city, in what was formerly the port, are especially interesting for their fine mosaics, and for the impost-blocks interposed above the capitals of their columns to receive the springing of the pier-arches. These blocks appear to be somewhat crude modifications of the fragmentary architraves or entablatures employed in cla.s.sic Roman architecture to receive the springing of vaults sustained by columns, and became common in Byzantine structures (Fig. 73). The use of external arcading to give some slight adornment to the walls of the second of the above-named churches, and the round bell-towers of brick which adjoined both of them, were first steps toward the development of the "wall-veil" or arcaded decoration, and of the campaniles, which in later centuries became so characteristic of north Italian churches (see Chapter XIII.). In Rome the campaniles which accompany many of the mediaeval basilicas are square and pierced with many windows.

The basilican form of church became general in Italy, a large proportion of whose churches continued to be built with wooden roofs and with but slight deviations from the original type, long after the appearance of the Gothic style. The chief departures from early precedent were in the exterior, which was embellished with marble incrustations as in S. Miniato (Florence); or with successive stories of wall-arcades, as in many churches in Pisa and Lucca (see Fig. 90); until finally the introduction of cl.u.s.tered piers, pointed arches, and vaulting, gradually transformed the basilican into the Italian Romanesque and Gothic styles.

+SYRIA AND THE EAST.+ In Syria, particularly the central portion, the Christian architecture of the 3d to 8th centuries produced a number of very interesting monuments. The churches built by Constantine in Syria--the Church of the Nativity in Bethlehem (nominally built by his mother), of the Ascension at Jerusalem, the magnificent octagonal church on the site of the Temple, and finally the somewhat similar church at Antioch--were the most notable Christian monuments in Syria. The first three on the list, still extant in part at least, have been so altered by later additions and restorations that their original forms are only approximately known from early descriptions. They were all of large size, and the octagonal church on the Temple platform was of exceptional magnificence.[16] The columns and a part of the marble incrustations of the early design are still visible in the "Mosque of Omar," but most of the old work is concealed by the decoration of tiles applied by the Moslems, and the whole interior aspect altered by the wood-and-plaster dome with which they replaced the simpler roof of the original.

[Footnote 16: Fergusson (_History of Architecture_, vol. ii., pp.

408, 432) contends that this was the real Constantinian church of the Holy Sepulchre, and that the one called to-day by that name was erected by the Crusaders in the twelfth century. The more general view is that the latter was originally built by Constantine as the Church of the Sepulchre, though subsequently much altered, and that the octagonal edifice was also his work, but erected under some other name. Whether this church was later incorporated in the "Mosque of Omar," or merely furnished some of the materials for its construction, is not quite clear.]

[Ill.u.s.tration: FIG. 69.--CHURCH AT KALB LOUZEH.]

Christian architecture in Syria soon, however, diverged from Roman traditions. The abundance of hard stone, the total lack of clay or brick, the remoteness from Rome, led to a peculiar independence and originality in the forms and details of the ecclesiastical as well as of the domestic architecture of central Syria. These innovations upon Roman models resulted in the development of distinct types which, but for the arrest of progress by the Mohammedan conquest in the seventh century, would doubtless have inaugurated a new and independent style of architecture. Piers of masonry came to replace the cla.s.sic column, as at Tafkha (third or fourth century), Rouheiha and Kalb Louzeh (fifth century? Fig. 69); the ceilings in the smaller churches were often formed with stone slabs; the apse was at first confined within the main rectangle of the plan, and was sometimes square. The exterior a.s.sumed a striking and picturesque variety of forms by means of turrets, porches, and gables. Singularly enough, vaulting hardly appears at all, though the arch is used with fine effect. Conventional and monastic groups of buildings appear early in Syria, and that of +St. Simeon Stylites+ at Kelat Seman is an impressive and interesting monument. Four three-aisled wings form the arms of a cross, meeting in a central octagonal open court, in the midst of which stood the column of the saint. The eastern arm of the cross forms a complete basilica of itself, and the whole cross measures 330 300 feet. Chapels, cloisters, and cells adjoin the main edifice.

[Ill.u.s.tration: FIG. 70.--CATHEDRAL AT BOZRAH.]

Circular and polygonal plans appear in a number of Syrian examples of the early sixth century. Their most striking feature is the inscribing of the circle or polygon in a square which forms the exterior outline, and the use of four niches to fill out the corners. This occurs at Kelat Seman in a small double church, perhaps the tomb and chapel of a martyr; in the cathedral at +Bozrah+ (Fig. 70), and in the small domical church of +St. George+ at +Ezra+. These were probably the prototypes of many Byzantine churches like St. Sergius at Constantinople, and San Vitale at Ravenna (Fig. 74), though the exact dates of the Syrian churches are not known. The one at Ezra is the only one of the three which has a dome, the others having been roofed with wood.

The interesting domestic architecture of this period is preserved in whole towns and villages in the Hauran, which, deserted at the Arab conquest, have never been reoccupied and remain almost intact but for the decay of their wooden roofs. They are marked by dignity and simplicity of design, and by the same picturesque ma.s.sing of gables and roofs and porches which has already been remarked of the churches. The arches are broad, the columns rather heavy, the mouldings few and simple, and the scanty carving vigorous and effective, often strongly Byzantine in type.

Elsewhere in the Eastern world are many early churches of which even the enumeration would exceed the limits of this work. Salonica counts a number of basilicas and several domical churches. The church of +St.

George+, now a mosque, is of early date and thoroughly Roman in plan and section, of the same cla.s.s with the Pantheon and the tomb of Helena, in both of which a ma.s.sive circular wall is lightened by eight niches. At Angora (Ancyra), Hierapolis, Pergamus, and other points in Asia Minor; in Egypt, Nubia, and Algiers, are many examples of both circular and basilican edifices of the early centuries of Christianity. In Constantinople there remains but a single representative of the basilican type, the church of +St. John Studius+, now the Emir Akhor mosque.

+MONUMENTS+: ROME: 4th century: St. Peter's, Sta. Costanza, 330?; Sta. Pudentiana, 335 (rebuilt 1598); tomb of St. Helena; Baptistery of Constantine; St. Paul's beyond the Walls, 386; St.

John Lateran (wholly remodelled in modern times). 5th century: Baptistery of St. John Lateran; Sta. Sabina, 425; Sta. Maria Maggiore, 432; S. Pietro in Vincoli, 442 (greatly altered in modern times). 6th century: S. Lorenzo, 580 (the older portion in two stories); SS. Cosmo e Damiano. 7th century: Sta. Agnese, 625; S. Giorgio in Velabro, 682. 8th century: Sta. Maria in Cosmedin; S. Crisogono. 9th century: S. Nereo ed Achilleo; Sta. Pra.s.sede; Sta. Maria in Dominica. 12th and 13th centuries: S. Clemente, 1118; Sta. Maria in Trastevere; S. Lorenzo (nave); Sta. Maria in Ara Coeli. RAVENNA: Baptistery of S. John, 400 (?); S. Francesco; S. Giovanni Evangelista, 425; Sta. Agata, 430; S. Giovanni Battista, 439; tomb of Galla Placidia, 450; S. Apollinare Nuovo, 500-520; S. Apollinare in Cla.s.se, 538; St. Victor; Sta. Maria in Cosmedin (the Arian Baptistery); tomb of Theodoric (Sta. Maria della Rotonda, a decagonal two-storied mausoleum, with a low dome cut from a single stone 36 feet in diameter), 530-540. ITALY IN GENERAL: basilica at Parenzo, 6th century; cathedral and Sta.

Fosca at Torcello, 640-700; at Naples Sta. Rest.i.tuta, 7th century; others, mostly of 10th-13th centuries, at Murano near Venice, at Florence (S. Miniato), Spoleto, Toscanella, etc.; baptisteries at Asti, Florence, Nocera dei Pagani, and other places. IN SYRIA AND THE EAST: basilicas of the Nativity at Bethlehem, of the Sepulchre and of the Ascension at Jerusalem; also polygonal church on Temple platform; these all of 4th century. Basilicas at Bakouzah, Ha.s.s, Kelat Seman, Kalb Louzeh, Rouheiha, Tourmanin, etc.; circular churches, tombs, and baptisteries at Bozrah, Ezra, Ha.s.s, Kelat Seman, Rouheiha, etc.; all these 4th-8th centuries. Churches at Constantinople (Holy Wisdom, St. John Studius, etc.), Hierapolis, Pergamus, and Thessalonica (St. Demetrius, "Eski Djuma"); in Egypt and Nubia (Djemla, Announa, Ibreem, Siout, etc.); at Orleansville in Algeria. (For churches, etc., of 8th-10th centuries in the West, see Chapter XIII.)

CHAPTER XI.

BYZANTINE ARCHITECTURE.

BOOKS RECOMMENDED: As before, Essenwein, Hubsch, Von Quast. Also, Bayet, _L'Art Byzantin_. Choisy, _L'Art de batir chez les Byzantins_. Lethaby and Swainson, _Sancta Sophia_. Ongania, _La Basilica di San Marco_. Pulgher, _Anciennes eglises Byzantines de Constantinople_. Salzenberg, _Altchristliche Baudenkmale von Constantinopel_. Texier and Pullan, _Byzantine Architecture_.

+ORIGIN AND CHARACTER.+ The decline and fall of Rome arrested the development of the basilican style in the West, as did the Arab conquest later in Syria. It was otherwise in the new Eastern capital founded by Constantine in the ancient Byzantium, which was rising in power and wealth while Rome lay in ruins. Situated at the strategic point of the natural highway of commerce between East and West, salubrious and enchantingly beautiful in its surroundings, the new capital grew rapidly from provincial insignificance to metropolitan importance. Its founder had embellished it with an extraordinary wealth of buildings, in which, owing to the scarcity of trained architects, quant.i.ty and cost doubtless outran quality. But at least the tameness of blindly followed precedent was avoided, and this departure from traditional tenets contributed undoubtedly to the originality of Byzantine architecture. A large part of the artisans employed in building were then, as now, from Asia Minor and the aegean Islands, Greek in race if not in name. An Oriental taste for brilliant and harmonious color and for minute decoration spread over broad surfaces must have been stimulated by trade with the Far East and by constant contact with Oriental peoples, costumes, and arts. An Asiatic origin may also be a.s.signed to the methods of vaulting employed, far more varied than the Roman, not only in form but also in materials and processes. From Roman architecture, however, the Byzantines borrowed the fundamental notion of their structural art; that, namely, of distributing the weights and strains of their vaulted structures upon isolated and ma.s.sive points of support, strengthened by deep b.u.t.tresses, internal or external, as the case might be. Roman, likewise, was the use of polished monolithic columns, and the incrustation of the piers and walls with panels of variegated marble, as well as the decoration of plastered surfaces by fresco and mosaic, and the use of _opus sectile_ and _opus Alexandrinum_ for the production of sumptuous marble pavements. In the first of these processes the color-figures of the pattern are formed each of a single piece of marble cut to the shape required; in the second the pattern is compounded of minute squares, triangles, and curved pieces of uniform size. Under these combined influences the artists of Constantinople wrought out new problems in construction and decoration, giving to all that they touched a new and striking character.

There is no absolute line of demarcation, chronological, geographical, or structural, between Early Christian and Byzantine architecture. But the former was especially characterized by the basilica with three or five aisles, and the use of wooden roofs even in its circular edifices; the vault and dome, though not unknown, being exceedingly rare.

Byzantine architecture, on the other hand, rarely produced the simple three-aisled or five-aisled basilica, and nearly all its monuments were vaulted. The dome was especially frequent, and Byzantine architecture achieved its highest triumphs in the use of the _pendentive_, as the triangular spherical surfaces are called, by the aid of which a dome can be supported on the summits of four arches spanning the four sides of a square, as explained later. There is as little uniformity in the plans of Byzantine buildings as in the forms of the vaulting. A few types of church-plan, however, predominated locally in one or another centre; but the controlling feature of the style was the dome and the constructive system with which it was a.s.sociated. The dome, it is true, had long been used by the Romans, but always on a circular plan, as in the Pantheon.

It is also a fact that pendentives have been found in Syria and Asia Minor older than the oldest Byzantine examples. But the special feature characterizing the Byzantine dome on pendentives was its almost exclusive a.s.sociation with plans having piers and columns or aisles, with the dome as the central and dominant feature of the complex design (see plans, Figs. 74, 75, 78). Another strictly Byzantine practice was the piercing of the lower portion of the dome with windows forming a circle or crown, and the final development of this feature into a high drum.

+CONSTRUCTION.+ Still another divergence from Roman methods was in the subst.i.tution of brick and stone masonry for concrete. Brick was used for the ma.s.s as well as the facing of walls and piers, and for the vaulting in many buildings mainly built of stone. Stone was used either alone or in combination with brick, the latter appearing in bands of four or five courses at intervals of three or four feet. In later work a regular alternation of the two materials, course for course, was not uncommon.

In piers intended to support unusually heavy loads the stone was very carefully cut and fitted, and sometimes tied and clamped with iron.

Vaults were built sometimes of brick, sometimes of cut stone; in a few cases even of earthenware jars fitting into each other, and laid up in a continuous contracting spiral from the base to the crown of a dome, as in San Vitale at Ravenna. Ingenious processes for building vaults without centrings were made use of--processes inherited from the drain-builders of ancient a.s.syria, and still in vogue in Armenia, Persia, and Asia Minor. The groined vault was common, but always approximated the form of a dome, by a longitudinal convexity upward in the intersecting vaults. The aisles of Hagia Sophia[17] display a remarkable variety of forms in the vaulting.

[Footnote 17: "St. Sophia," the common name of this church, is a misnomer. It was not dedicated to a saint at all, but to the Divine Wisdom (Hagia Sophia), which name the Turks have retained in the softened form "Aya Sofia."]

[Ill.u.s.tration: FIG. 71.--DIAGRAM OF PENDENTIVES.]

+DOMES.+ The dome, as we have seen, early became the most characteristic feature of Byzantine architecture; and especially the dome on pendentives. If a hemisphere be cut by five planes, four perpendicular to its base and bounding a square inscribed therein, and the fifth plane parallel to the base and tangent to the semicircular intersections made by the first four, there will remain of the original surface only four triangular s.p.a.ces bounded by arcs of circles. These are called _pendentives_ (Fig. 71 a). When these are built up of masonry, each course forms a species of arch, by virtue of its convexity. At the crown of the four arches on which they rest, these courses meet and form a complete circle, perfectly stable and capable of sustaining any superstructure that does not by excessive weight disrupt the whole fabric by overthrowing the four arches which support it. Upon these pendentives, then, a new dome may be started of any desired curvature, or even a cylindrical drum to support a still loftier dome, as in the later churches (Fig. 71 b). This method of covering a square is simpler than the groined vault, having no sharp edges or intersections; it is at least as effective architecturally, by reason of its greater height in the centre; and is equally applicable to successive bays of an oblong, cruciform, and even columnar building. In the great cisterns at Constantinople vast areas are covered by rows of small domes supported on ranges of columns.

The earlier domes were commonly pierced with windows at the base, this apparent weakening of the vault being compensated for by strongly b.u.t.tressing the piers between the windows, as in Hagia Sophia. Here forty windows form a crown of light at the spring of the dome, producing an effect almost as striking as that of the simple _oculus_ of the Pantheon, and celebrated by ancient writers in the most extravagant terms. In later and smaller churches a high drum was introduced beneath the dome, in order to secure, by means of longer windows, more light than could be obtained by merely piercing the diminutive domes.

b.u.t.tressing was well understood by the Byzantines, whose plans were skilfully devised to provide internal abutments, which were often continued above the roofs of the side-aisles to prop the main vaults, precisely as was done by the Romans in their thermae and similar halls.

But the Byzantines, while adhering less strictly than the Romans to traditional forms and processes, and displaying much more ready contrivance and special adaptation of means to ends, never worked out this pregnant structural principle to its logical conclusion as did the Gothic architects of Western Europe a few centuries later.

+DECORATION+. The exteriors of Byzantine buildings (except in some of the small churches of late date) were generally bare and lacking in beauty. The interiors, on the contrary, were richly decorated, color playing a much larger part than carving in the designs. Painting was resorted to only in the smaller buildings, the more durable and splendid medium of mosaic being usually preferred. This was, as a rule, confined to the vaults and to those portions of the wall-surfaces embraced by the vaults above their springing. The colors were brilliant, the background being usually of gold, though sometimes of blue or a delicate green.

Biblical scenes, symbolic and allegorical figures and groups of saints adorned the larger areas, particularly the half-dome of the apse, as in the basilicas. The smaller vaults, the soffits of arches, borders of pictures, and other minor surfaces, received a more conventional decoration of crosses, monograms, and set patterns.

[Ill.u.s.tration: FIG. 72.--SPANDRIL. HAGIA SOPHIA.]

The walls throughout were sheathed with slabs of rare marble in panels so disposed that the veining should produce symmetrical figures. The panels were framed in billet-mouldings, derived perhaps from cla.s.sic dentils; the billets or projections on one side the moulding coming opposite the s.p.a.ces on the other. This seems to have been a purely Byzantine feature.

+CARVED DETAILS.+ Internally the different stories were marked by horizontal bands and cornices of white or inlaid marble richly carved.

The arch-soffits, the archivolts or bands around the arches, and the spandrils between them were covered with minute and intricate incised carving. The motives used, though based on the acanthus and anthemion, were given a wholly new aspect. The relief was low and flat, the leaves sharp and crowded, and the effect rich and lacelike, rather than vigorous. It was, however, well adapted to the covering of large areas where general effect was more important than detail. Even the capitals were treated in the same spirit. The impost-block was almost universal, except where its use was rendered unnecessary by giving to the capital itself the ma.s.sive pyramidal form required to receive properly the spring of the arch or vault. In such cases (more frequent in Constantinople than elsewhere) the surface of the capital was simply covered with incised carving of foliage, basketwork, monograms, etc.; rudimentary volutes in a few cases recalling cla.s.sic traditions (Figs.

72, 73). The mouldings were weak and poorly executed, and the vigorous profiles of cla.s.sic cornices were only remotely suggested by the characterless aggregations of mouldings which took their place.

[Ill.u.s.tration: FIG. 73.--CAPITAL WITH IMPOST BLOCK, S. VITALE.]