Procopius, De aedif. I, i, 23 ff: The Emperor, disregarding all considerations of expense, hastened to begin construction and raised craftsmen from the whole world. It was Anthemius of Tralles, the most learned man in the discipline called engineering (mêchanikê), not only of all his contemporaries, but also as compared to those who had lived long before him, that ministered to the Emperor's zeal by regulating the work of the builders and preparing in advance designs of what was going to be built. He had as partner another engineer (mêchanopoios) called Isidore, a native of Miletus, who was intelligent in all respects and worthy to serve the Emperor Justinian.
So the church has been made a spectacle of great beauty, stupendous to those who see it and altogether incredible to those who hear of it. Its breadth and length have been so fittingly proportioned that it may without impropriety be described as being both very long and extremely broad. And it boasts of an ineffable beauty, for it subtly combines its mass with the harmony of its proportions, having neither any excess nor any deficiency, inasmuch as it is more pompous than ordinary [buildings] and considerably more decorous than those which are huge beyond measure; and it abounds exceedingly in gleaming sunlight. You might say that the [interior] space is not illuminated by the sun from the outside, but that the radiance is generated within, so great an abundance of light bathes this shrine all round. The face of the church-this would be the part turned towards the rising sun, intended for the celebration of God's mysteries-has been wrought in the following fashion. A construction of masonry rises from the ground, not in a straight line, but gradually drawing back from its sides and receding in the middle, so as to describe a semi-circular shape which is called a half-cylinder by specialists, and this towers to a precipitous height. The extremity (huperbolê) of this structure terminates in the fourth part of a sphere,92 and above it another crescent-shaped form (mênoides)93 is lifted up by the adjoining parts of the building, wonderful in its beauty yet altogether terrifying by the apparent precariousness of its composition. For it seems somehow not to be raised in a firm manner, but to soar aloft to the peril of those who are there; and yet, it is supported with quite extraordinary firmness and security. On either side of these [elements] columns are placed on the ground, and these, too, do not stand in a straight line, but retreat inward in a half-circle as if making way for one another in a dance,94 and above them is suspended a crescent-shaped form. Opposite the eastern wall is another one that contains the entrances, and on either side of the latter both the columns and the superstructure stand in a half-circle, in a manner very similar to what has been described. In the middle of the church there rise four man-made eminences which are called piers (pessoi), two on the north and two on the south, opposite and equal to one another, each pair having between them exactly four columns. The eminences are built to a great height and are composed of big stones, carefully selected and skillfully fitted together by the masons. As you see them, you could suppose them to be precipitous mountain peaks. Upon these are placed four arches so as to form a square, their ends coming together in pairs and made fast at the summit of those piers, while the rest of them rises to an immense height. Two of the arches, namely those facing the rising and the setting sun, are suspended over empty air, while the others have beneath them some kind of structure (oikodomia) and rather tall95 columns. Above the arches the construction rises in a circle: it is through this that the first light of day always smiles. Indeed, I believe it towers above the whole earth, and the structure has gaps at short intervals,96 being intentionally interrupted so that the openings corresponding to the divisions in the masonry are channels of constant illumination. And since the arches are joined together on a square plan, the intervening construction assumes the form of four triangles.97 The bottom end of each triangle, being pressed together by the conjunction of the arches, causes the lower angle to be acute, but as it rises it becomes wider by the intervening space and terminates in the arc of a circle, which it supports, and forms the remaining [two] angles at that level. Rising above this circle is an enormous spherical dome which makes the building exceptionally beautiful. It seems not to be founded on solid masonry, but to be suspended from heaven by that golden chain98 and so cover the space. All of these elements, marvellously fitted together in mid-air, suspended from one another and reposing only on the parts adjacent to them, produce a unified and most remarkable harmony in the work, and yet do not allow the spectators to rest their gaze upon any one of them for a length of time, but each detail readily draws and attracts the eye to itself. Thus the vision constantly shifts round, and the beholders are quite unable to select any particular element which they might admire more than all the others. No matter how much they concentrate their attention on this side and that, and examine everything with contracted eyebrows, they are unable to understand the craftsmanship and always depart from there amazed by the perplexing spectacle. So much, then, for this.
It was by means of many devices that the Emperor Justinian and the engineers Anthemius and Isidore gave stability to the church, suspended as it is in mid-air. Most of these are beyond my comprehension and I find it impossible to express them in words; one device only I shall describe here in order to demonstrate the strength of the whole work. It is as follows: The piers which I have just mentioned are not built like ordinary masonry, but in this fashion. Courses of stone have been laid in a four-square shape99; they are hard by nature, but worked smooth, and those of them that were intended to form the lateral projections of the piers have been cut at an angle, while the ones that were assigned an intermediary position have been made rectangular. These were joined together not with lime which they call unslaked, nor with asphalt, the pride of Semiramis in Babylon, nor with any other similar substance, but with lead poured into the interstices, which has penetrated into all the intervening spaces and having hardened in the joints, binds the stones together.100 This, then, was built in the above manner; but let us now proceed to the remaining parts of the church.
The entire ceiling has been overlaid with pure gold which combines beauty with ostentation, yet the refulgence from the marble prevails, vying as it does with that of the gold. There are two colonnades (stoai), one on each side, not separated from the church by any structural element, but actually adding to the measure of its width and extending to its whole length, while their height is less than that of the building. They, too, have a vaulted ceiling (orophê tholos) adorned with gold. One of these colonnades is assigned to men for their devotions, while the other is used by women for the same purpose. However, there is no difference or any distinction between the two, but their very equality and similarity contribute to the beauty and adornment of the church. But who could describe the galleries (huperôa) of the women's part (gunaikônitis) or enumerate the many colonnades and columned courts (peristuloi aulai) by means of which the church is encompassed? Who could recount the beauty of the columns and the marbles with which the church is adorned? One might imagine that one has chanced upon a meadow in full bloom. For one would surely marvel at the purple hue of some, the green of others, at those on which the crimson blooms, at those that flash with white, at those, too, which Nature, like a painter, has varied with the most contrasting colors. Whenever one goes to this church to pray, one understands immediately that this work has been fashioned not by human power or skill, but by the influence of God. And so the visitor's mind is lifted up to God and floats aloft, thinking that He cannot be far away, but must love to dwell in this place which He himself has chosen. And as for the treasure of this church-the [vessels of] gold and silver and precious stones which the Emperor Justinian has dedicated here-it is impossible to give an exact account of all of them. I shall allow my readers to form an estimate by means of a single example. That part of the church which is especially sacred and accessible to priests only-it is called the sanctuary (thusiastêrion)-exhibits forty thousand pounds of silver.
So the church of Constantinople, which men are wont to call the Great Church has been wrought in this fashion by the Emperor Justinian. It was not by money alone that the emperor built it, but with toil of the mind and the other qualities of the soul, as I am about to relate. One of the arches that I have just mentioned (engineers call them 1ôroi),101 namely the one to the east, had already been raised on either side, but had not been completed in the middle, and was still waiting. The piers on top of which the structure was being built, unable to bear the mass that was pressing down on them, somehow or other suddenly started to break away and seemed to be on the point of collapsing. So the staff of Anthemius and Isidore, terrified at what had happened and having lost confidence in their skill, referred the matter to the emperor. And the emperor, impelled by I know not what, but, I suppose, by God (since he is not an engineer), immediately commanded them to complete the curve of that arch. "For," he said, "when it is supported by itself, it will no longer need the piers (pessoi) beneath it."102 If this story were unwitnessed, I am sure it would seem to be a piece of flattery and altogether incredible, but since there exist many witnesses of what happened at that time, we need not be reluctant to tell the rest of the story. So the craftsmen carried out the orders, and he entire arch was securely suspended, thus confirming by experiment the validity of his idea. This, then, was finished in the above manner; but in the case of the other arches, namely those turned toward the south and the north, the following chanced to happen. The so called lôroi, swelled out by the masonry of the church,103 were already in the air, but everything beneath them was suffering under their weight and the columns that are there were shedding little flakes as if being scraped.104 Once again the engineers became dispirited by what had happened and reported their plight to the emperor. And once again the emperor solved the problem by the following device. He commanded that the extremities of the parts that has suffered, namely what came in contact with the arches, should be immediately removed and inserted much later, at such time when the moisture of the masonry had sufficiently abated. They followed these precepts, and thereafter the structure survived secure. From this work the emperor enjoys a kind of added testimonial.
The Rebuilding of St. Sophia
Agathias, Hist. V, 9, 2-5: He [Justinian] showed particular concern for the Great Church of God which he rebuilt in a conspicuous and admirable form from the very foundations after it had been burnt down by the populace, and endowed it with exceedingly great size, a majestic shape and an adornment of various quarried materials. He compacted it of baked brick and mortar, and in many places bound it together with iron, but made no use of wood so that the church should no longer prove combustible. The architect and creator of all these things was that Anthemius whom I mentioned not long ago. When, as a result of the earthquake,106 the church had lost the central part of the roof-the part that towers over all the others-the emperor repaired it in a more secure fashion and raised it to a greater height. Since Anthemius had long been dead, Isidore the Younger and the other engineers reviewed among themselves the former design and, by reference to what had remained, they judged the part that had fallen down, i.e., its nature and its faults. They left the east and west arches as they were in their former places, but in the case of the north and south ones they extended inward that part of the construction which lies on a curve and gradually increased its width so as to make them [the north and south arches] agree more closely with the others and observe the harmony of equal sides. In this way they were able to reduce the unevenness of the void and to gain a little on the extent of the space, i.e., that part of it which produced a rectangular figure. Upon these [new] arches they set up once again that circle or hemisphere (or whatever alse they call it) which dominates the centre of the building. As a result, the dome naturally became more even and well-curved, conforming altogether to the [correct geometrical] figure. It was narrower and steeper so that it did not strike spectators with as much amazement as before, but it was far more securely set up.
Theophanes, A.M. 6051, pp. 232-33:107 On May 7th of this year , a Tuesday, in the 5th hour, while the dome of the Great Church was being repaired-for it had been cracked by the preceding earthquakes- and while the Isaurians108 were at work, the eastern part of the vault (prohupostolê) of the holy sanctuary fell down and crushed the ciborium, the altar-table and the ambo. The engineers were censured because, avoiding the expense, they had not made the suspension [secure] from below, but had tunnelled the piers upholding the dome, and for this reason they had not held. Having grasped this, the most-pious emperor erected new piers to receive the dome,109 and so the dome was built and raised by more than twenty feet in height as compared to the original Structure.
Malalas, p. 495: In the same indiction [562/3]110 took place the second consecration of the most-holy Great Church. As compared to its old form, the dome was made thirty feet higher and they also made two additional arches (kamarai), i.e., the northern and the southern one.
92 The semidome of the apse.
93 The eastern semidome.
94 Procopius is here referring to the colonnades of the exedras.
95 I have adopted here the reading of cod. Vaticanus 1065, kionas makrous in preference to kionas mikrous ("small columns") as printed in the Teubner and Loeb editions. The original form of the north and south tympana is not to that of the great west window which is divided by tall mullions.
96The windows of the dome.
97 The pendentives of the dome.
98 Iliad, VIII, 19.
99 Strictly speaking, the main piers are not rectangular (see plan).
100 Lead, of course, was laid in sheets, not poured.
101 From Lat. lorum meaning a thong. The lôros was also the name of a long ceremonial scarf worn my consuls and emperors.
102 This passage is not altogether clear. The meaning, I believe, is not, of course, that the arch, once completed, will not longer need the piers, but rather that it will not be making such heaving demands on the piers. In the Loeb ed. (p.31) it is suggested that Procopius is using the term pessoi in two different senses: (1) piers, (2) the props of the wooden centering. I find it difficult to accept this explanation. There can be no doubt that the eastern arch was built on a centering; what happened, however, is that as the voussoirs were being laid, the piers started tilting laterally. Justinian would have been guilty of a non sequitur if he had said that the arch, when completed, would not have needed the centering any longer: no arch does.
103 I have given a literal translation of this somewhat obscure phrase. The swelling in question may refer to the pendentives which, naturally, would have exerted added weight on the arches. Procopius seems to be saying that the north and south tympana were erected simultaneously with the arches and that the latter, being still damp and therefore in the process of settling, weighed down heavily on the underlying masonry.
104 This is an accurate description of the behavior of marble when subjected to great pressure.
105 Cf. G. Millet, "La coupole primitive de Ste. Sophie," Revue belge de pilologie et dhistoire, II (1923), 599 ff.; K.J. Conant, "The First Dome of St. Sophia and its Rebuilding," Bulletin of the Byzantine Institute, I (1946), 71 ff.
106 The earthquake occurred in December 557, and the collapse of the dome in 558.
107 This passage probably derives from the complete Chronicle of Malalas, now lost. It also appears, with minor variations, in the abbreviated Malalas, CSHB, pp. 489 f. and in other chronicles. Cedrenus, CSHB, I, 676 f. adds: "He [Justinian] also made outside the church the four spiral ramps opposite the interior piers. These he planted in the ground and raised as far as the dome so as to buttress the arches. At the same time he made the altar-table, an incomparable work."
108 Cf. C. Mango, "Isaurian Builders," Polychronion: Fetschrift F. Dölger (Heidelberg, 1966), pp. 358 ff.
110 The reconscration was celebrated on December 24, 562.