After the Hagia Sophia’s completion, the court historian, Prokopios, wrote about it. We owe him a debt for his writing, because little else exists about the church th ksuch detailed description. He begins the part about the church itself:
So the church has become a spectacle of marvelous beauty, overwhelming to those who see it, but to those who know it by hearsay altogether incredible. For it soars to a height to match the sky, and as if surging up from amongst the other buildings it stands on high and looks down upon the remainder of the city, adorning it, because it is a part of it, but glorying in its own beauty, because, though a part of the city and dominating it, it at the same time towers above it to such a height that the whole city is viewed from there as from a watch-tower (Prokopios, pg.13).
The part of the church that had the most time devoted to it was the dome. It was an exquisite feat. In order to build the dome and secure it, the architects Anthemius and Isidore designed the dome to be supported with half-domes, or semi-domes, and the semi-domes were supported by smaller, radiating domes. The central dome itself rests upon four arches which are attached to massive piers. At the base of the dome is a ring of forty windows, which lightened the dome, and allowed light to stream inside throughout the nave. Prokopios wrote about the dome, marveling at the sight of it:
For it proudly reveals its mass and the harmony of its proportions, having neither any excess nor deficiency, since it is both more pretentious than the buildings to which we are accustomed, and considerably more noble than those which are merely huge, and it abounds exceedingly in sunlight and in the reflection of the sun’s rays from the marble. Indeed one might say that its interior is not illuminated from without by the sun, but that the radiance comes into being within it, such an abundance of light bathes this shrine (Prokopios, pg. 17).
Justinian had seen the Pantheon in Rome, and was very impressed with it. He also liked the shape and structure of the basilica. In order to support the dome the arches had to be supported on the sides with massive piers, so the arches would not collapse from the weight of the dome. The piers were placed in a square on the floor beneath the dome. This square shape defined with area supporting the dome, and the circular dome was made to rest upon the structures forming a square. This geometrical configuration had meaning to the ancient geometers, mathematicians, and philosophers — the circle represented Heaven and the Square represented Earth. The circle in the square configuration meant ‘Heaven on Earth’ — a beautiful meaning for a beautiful building. Prokopios described the structure and the complexities of the dome:
A structure of masonry (oikodomia) is built up from the ground, not made in a straight line, but gradually curving inward on its flanks and receding at the middle, so that it forms the shape of half a circle, which those who are skilled in such matters call a half-cylinder (hêmi-kylindron); and so it rises precipitously to a height. The upper part of this structure ends in the fourth part of a sphere (sphaira), and above it another crescent-shaped (mênoeides) the seeming insecurity of its composition altogether terrifying. For it seems somehow to float in the air on no firm basis, but to be poised aloft to the peril of those inside it….(Prokopios, pg.17).
Prokopios conveys the breathtaking reactions that this church received upon her consecration. Clearly, this church was magnificent. It would remain the largest church in the world for almost a thousand years. He describes the dome’s visual effect:
And upon this circle rests the huge spherical dome (sphairoeidês tholos) which makes the structure exceptionally beautiful. Yet it seems not to rest upon solid masonry, but to cover the space with its golden dome (sphaira) as if it is suspended by a golden chain from Heaven” (Prokopios, pg. 21).