A History of Architecture in all Countries, Volume 1, 3rd ed. / From the Earliest Times to the Present Day

by James Fergusson

Churches with Domes.

Whether the dome of the Pantheon at Rome (p. [320]) was erected in the time of the Antonines, or before the time of Augustus, as was formerly supposed, it is evident that the Romans had conquered the difficulties of domic construction long before the transference of the seat of power to Byzantium; the Pantheon being, up to this hour, the largest (single) dome ever constructed by the hand of man. Simple and grand as it undoubtedly is, it had several glaring defects in its design which the Byzantines set themselves to remedy. The first was that twice the necessary amount of materials was consumed in its construction. The second, that the mode of lighting by a hole in the roof, which also admitted the rain and the snow, was most objectionable before the invention of glass. The third, that a simply circular plan is always unmeaning and inconvenient. A fourth, that a circular building can hardly, by any contrivance, be made to fit on to any other buildings or apartments.

In the Minerva Medica (Woodcut No. [229]) great efforts were made, but not quite successfully, to remedy these defects. The building would not fit on to any others, and, though an improvement on the design of the Pantheon, was still far from perfect.

300. Diagram of Byzantine Arrangement.

301. Diagram of Byzantine Pendentives.

The first step the Byzantines made was to carry the dome on arches resting on eight piers enclosing an octagon A (Woodcut No. [300]); this enabled them to obtain increased space, to provide nave, choir, and transepts, and by throwing out niches on the diagonal lines, virtually to obtain a square hall in the centre. The difference between the octagon and circle is so slight, that by corbelling out above the extrados of the arches, a circular base for the dome was easily obtained B. The next step was to carry the dome on arches resting on four piers, and their triumph was complete when by the introduction of pendentives—represented by the shaded parts at D (Woodcut No. [301]), they were enabled to place the circular dome on a square compartment. The pendentives and dome thus projected formed part of a sphere, the radius of which was the half-diagonal of the square compartment. Constructively it would probably have been easier to roof the space by an intersecting vault; and even if of 100 or 150 ft. span it would without difficulty have been effected. The difference between the intersecting vault and the dome (as shown in Woodcuts [302] and [303]; the former the tomb of Galla Placidia, built 450 A.D., the latter the chapel of St. Peter Crysologus attached to the archiepiscopal palace of about the same date, and both in Ravenna) is perhaps the most striking contrast the history of architecture affords between mechanical and ornamental construction. Both are capable of being ornamented to the same extent and in the same manner; but the difference of form rendered the dome a beautiful object in itself wholly irrespective of ornament, whereas the same cannot always be said of the intersecting barrel vault. Altogether, the effect would have been architecturally so infinitely inferior, that we cannot but feel grateful to the Byzantines that they persevered, in spite of all mechanical temptations, till they reached the wonderful perfection of the dome of Sta. Sophia.

302. Tomb of Galla Placidia, Ravenna. (For plan see Woodcut No. [434].)

303. Chapel in Archiepiscopal Palace, Ravenna.

Among the earliest domical churches found in the East is that of St. George at Thessalonica. It is also, perhaps, the finest example of its class belonging strictly to that group which has been designated above as the Eastern Romanesque.

304. Plan of St. George at Thessalonica. Scale 100 ft. to 1 in.

As will be seen from the plan it is a circular apartment, 79 ft. in diameter, surrounded by walls 20 ft. in thickness, into which are cut seven great niches; two apparently serving as entrances, opposite one of which is a bema or presbytery of considerable importance and purely Christian form. The dome is hemispherical, pierced at its base by eight semi-circular lunettes, and externally covered and concealed by a wooden roof. This form of roof is first found in the West at Nocera dei Pagani (p. [547]), but the dome there is only half the diameter of this one, and of a very different form and construction. The dome of St. George’s retains its internal decorations, which are among the earliest as well as the most interesting Christian mosaics in existence.[^[224]] The architecture presented in them bears about the same relation to that in the Pompeiian frescoes which the Jacobæan does to classical architecture, and, mixed with Christian symbols and representations of Christian saints, makes up a most interesting example of early Christian decoration.

305. Section of Church of St. George at Thessalonica. (From Texier and Pullan.) Scale 50 ft. to 1 in.

306. View of Church of St. George at Thessalonica. (From Texier and Pullan.)

No inscriptions or historical indications exist from which the date of the church can be fixed. We are safe, however, in asserting that it was erected by Christians, for Christian purposes, subsequently to the age of Constantine. If we assume the year 400 as an approximate date we shall probably not err to any great extent, though the real date may be somewhat later.

307. Plan of Kalybe at Omm-es-Zeitoun (Syria). No Scale.

How early a true Byzantine form of arrangement may have been introduced we have no means of knowing; but as early as the year 285—according to De Vogüé—we have a Kalybe[^[225]] at Omm-es-Zeitoun, which contains all the elements of the new style. It is square in plan, with a circular dome in its centre for a roof. The wing walls which extend the façade are curious, but not singular. One other example, at least, is found in the Hauran, at Chaqqa, and there may be many more.

308. View of Kalybe at Omm-es-Zeitoun. (From De Vogüé.)

Still, in the Hauran they never seem quite to have fallen into the true Byzantine system of construction, but preferred one less mechanically difficult, even at the expense of crowding the floor with piers. In the church at Ezra, for instance, the internal octagon is reduced to a figure of sixteen sides before it is attempted to put a dome upon it, and all thought of beauty of form, either internally or externally, is abandoned in order to obtain mechanical stability—although the dome is only 30 ft. in diameter.

As the date of this church is perfectly ascertained (510) it forms a curious landmark in the style just anterior to the great efforts Justinian was about to make, and which forced it so suddenly into its greatest, though a short-lived, degree of perfection.

309. Plan of Church at Ezra. Scale 100 ft. to 1 in.

310. Section of Church at Ezra. Scale 50 ft. to 1 in.