Brief description of the architecture of Hagia Sophia

Christopher Glass

Revised February 3, 2003

Note: a good bit of the following is skimmed from Eugene Kleinbauer’s book Saint Sophia at Constantinople: Singulariter in Mundo 1999, William L. Bauhan, Dublin NH (cover is Figure 1, with a 1680 view)

Figure 0: Cover of Kleinbauer’s book

History: On January 13, 532, a riot staged by the supporters of two rival horse-racing teams at the Hippodrome (the Blues and the Greens) escalated into a tax revolt against the Emperor Justinian (subsequently called the Great). As he was about to flee the city, his wife Theodora (whom some think of as the Greater) talked him into counterattacking with his Goth mercenaries, who rounded up the rioters in the hippodrome and massacred 30,000 to 50,000 of them. But by then the church of Hagia Sophia had been destroyed.i Justinian set about rebuilding.

Figure 0 Cutaway isometric from Great Architecture of the World

He chose Anthemius of Tralles and Isidore (the Elder) of Miletus, who were described as µεχηανιποιοσ “mechanipoioi”, neither of whom had designed a building. They were physicists and mathematicians, and the building, as Kleinbauer’s title indicates, would be “unique in the world”. Justinian was a unifier and a builder, credited with as many as 96 churches and 12 monasteries by John of Ephesus. He wanted not to replace the basilica but to surpass it.

Brief description of the architecture of Hagia Sophia Christopher Glass Page 2 of 5

What made the structure unique was its geometry, which combines central and longitudinal organization. [Figure 2 isometric] The overall plan is a square with a central dome, but a longitudinal character has been created by adding two half domes on the east and west ends of the central dome. [Figure 3 plan]. On the north and south the dome sits on colonnades that open onto side aisles.

Figure 0: Plan from Banister Fletcher 1924

The central dome rests on pendentives, curved sections of a larger diameter dome sliced off by the sides of the cubic box of the supporting structure. Diagram F in Figure 3 shows the geometry of the pendentives. The lateral thrust of the dome is resisted in the corners by the pendentives, at the east and the west by the counterthrust of the half domes, and on the north and south by wide arches braced by massive buttresses (Figure 4 section and Figure 5 exterior).

The construction was of brick (with stone columns where loads concentrate). As Diagram C on Figure 4 shows, the brick was not laid to for a true arch with bricks and joint radiating from the center; rather each course of large flat bricks was tilted in some but not all the way, allowing it to rest on the previous course until the mortar set. This way the dome could be built without the kind of scaffolding that we will see today as the surfaces are restored. The only formwork was a revolving armature called a trammel, which was a measuring device to ensure that the spherical shape remained accurate.

This structural extravagance is the more remarkable for incorporating forty windows at the point of maximum stress − the place Figure 0: Sections and Elevations from Bannister Fletcher 1924

Brief description of the architecture of Hagia Sophia Christopher Glass Page 3 of 5 where Hadrian’s Pantheon is the most solid. Note that while Hadrian’s dome is larger at 142.5 feet (15948 square feet), Hagia Sophia’s central space including the half domes is 107 by about 220 feet. (20441 square feet). The Pantheon has no windows other than the oculus in the center of the dome.

The Pantheon remains the

largest masonry dome. Hagia Sophia is also smaller than Brunelleschi’s Florence cathedral (138 ½ feet), Michelangelo’s St. Peter’s (137 ½) and Wren’s St. Paul’s (109 feet). Until steel and concrete technology advanced in the 19th century, no single spaces were larger than these.

Figure 0 Lithograph from the album by the Fossati brother

Unfortunately for the reputation of the µεχηανιποιοσ, the dome collapsed in 558, only 21 years after its construction was completed in 537. The principal cause was a series of earthquakes. The exact configuration of the first dome is unknown, but the replacement, which was executed by Isidore the Elder’s son Isidore the Younger, is thought to be “narrower and steeper” than the original and, in the reports of contemporaries, not as amazing. The second dome is what we see, though sections collapsed in 989 and 1343.

The north and south arches have bowed

outward between the buttresses − a phenomenon called “plastic creep” by engineers − so the dome is now slightly elliptical, about 2 meters wider than it is long. This settlement had occurred before the collapse of the first dome and probably contributed to its instability. Later changes including reducing the amount of opening in the tympanums (the areas under the north and south arches) and increasing the size of the buttresses. The minarets were adding by the Ottomans after the conquest of Constantinople in 1453, when the church was converted to a mosque. There were restorations in 1573and 1847-9, the latter by the Swiss architects Gaspare and Giuseppe Fossati.

I will not describe the program of the

decoration of the interior, or the whole issue of the iconoclasts and the images they and the Ottomans destroyed. The effect of the interior is perhaps best described by the poet Procopius,

Figure 0 Fossati

Brief description of the architecture of Hagia Sophia Christopher Glass Page 4 of 5 writing in Justinian’s time and quoted by Kleinbauer:

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 the church to pray, one realizes at once that it is not by

human power or skill, but by divine influence that this church has been so wonderfully built. The visitor’s mind is lifted up on high to God, feeling that he cannot be far away but must love to dwell in this place He himself has chosen. All this does not happen only when one sees the church for the first time, but the same thing occurs to the visitor on each successive occasion, as if the sight were ever a new one. No one has ever had a surfeit of this spectacle, but when persons are present in the building men rejoice in what they see, and when they are away from it, they take delight in talking of it.

And the writer of the

kontakion composed for the inauguration describes the light:

This sacred church of Christ

evidently outstrips in glory even the firmament above, for it does not offer a lamp of merely sensible light, but the shine of it bears aloft the divine illumination of the Sun of Truth and it is splendidly illumined throughout by day and by night by the rays of the Word of the Spirit, through which the eyes of the mind are enlightened by him (who said) ‘Let there be light!’, God.

Figure 0: Mosaic of Christ in the Gallery

Source Notes: The isometric rendering is from Great Architecture of the World, John Julius Norwich, General Editor; Random House, New York 1975, pp84-85.

The Banister Fletcher drawings are from A History of Architecture on the Comparative Method, Sir banister Fletcher F.A.R.I.B.A, F.S.I., F.R.G.S.; Charles Scribner’s Sons

Brief description of the architecture of Hagia Sophia Christopher Glass Page 5 of 5 The Fossati lithographs are from the album by the Fossati brothers, Aya Sofia Constantinople, London 1852, pl. 25 (Athens Gennadeios Library). These and the illustration of the mosaics are from the website of the Ecumenical Patriarchate of Constantinople: http://www.patriarchate.org/ecumenical_patriarchate/chapter_4/html/hagia_sophia.html

i The website of the Ecumenical Patriarchate of Constantinople (see note above) has the following history of the previous churches:

Only scant information is available on this first, timber-roofed, Hagia Sophia. The historian Socrates, writing in 440 his ecclesiastical history of the years 305 to 439, attributes the completion of the church in 360 to Constantius II (337-361), son of Constantine the Great. The passage reads: “.... at that time the king was building the Great Church, the one now called Sophia, adjoining it to that named Eirene...”. The proximity and relation of the two churches is obvious. The consecration ceremony was conducted by the Patriarch Eudoxius (360-370), in 360The Second Ecumenical Council was convened in Hagia Sophia in 381, during the reign of Theodosius I (378-395). Some twenty years later, on 20 June 404, the people angered by the banishment of John Chrysostom burned down the church .

Rebuilt by Theodosius 11 (408-450) and consecrated in 415, the church was again burnt to the ground by the rioting crowds during the Nika Revolt (15 January 532).