This is the third part of a five-part article. The remaining two parts will be published weekly on the next two Fridays.

The Plan of the Article:1

              Β. THE PANTHEON, ROME
                             Ξ. HAGIA SOPHIA, CONSTANTINOPLE


I am the Lord thy God who led thee out of the land of Egypt. Open thy mouth wide, and I will fill it. (Ps. 80:9)

Words are going to fail me in describing the greatest building in history, so prepare yourselves for that — this hierarchy of concentric forms does not lend itself to verbal exposition easily. The Hagia Sophia Cathedral was built in Constantinople in the 530s under Emperor Justinian, according to the design of two men, Anthemius of Tralles and Isidore of Miletus. It was notable for many reasons, such that it was the first fully pendentive dome and the largest interior space in the world. It was the central cathedral of the city and the empire. It was dedicated to Holy Wisdom, identified as the divine Logos, and its patronal feast day was Christmas, Holy Wisdom’s birthday in the flesh. I list data points from the top of its Wikipedia page because I honestly don’t know where to begin here.

Computer model of Hagia Sophia’s 6th-century form.

Architecturally speaking, the dome is the reason for the building, its origin and telos. But in construction it comes last. Should I describe it from the top down or the bottom up? You can’t have one without the other. The square base is broad, covering a lot of ground. The round dome represents a single point, so very, very high above the center. In between stands a holy mountain of a building, and necessarily so. The top of the building’s weight creates so much force — not just vertical but lateral — that it needs gradually wider and wider support as it descends.2


We saw at Morse Auditorium how a dome constructed over a square plot required not just the four walls rising from the square, but also spherical space within the four walls. Man needs not just a body but a soul in order to host God. The soul of Hagia Sophia is simply constituted but complexly described, a hierarchy of multiple layers.

The Semi-Domes

The four central arches under the dome, the pillars supporting them on one side, and the semi-domes supporting them on the other. (Source: Nova)

My favorite part (seemingly everyone’s favorite part) of the dome’s internal support structure is the quartet of triangular pendentives transferring weight to the four central arches. I’ll get to those eventually, but the truth is they do not begin to describe how it is that this building stands. Those four central arches would explode outward from the lateral thrust of the weight if not thoroughly buttressed on all four sides.

The four central arches under the dome, the pillars supporting them on one side, and the semi-domes supporting them on the other. (Source: Nova)


On the outside of the building, to the north and south,3 two of the four arches are buttressed by massive piers which are architecturally essential but symbolically external and invisible to the interior. To the east and west of the central dome, though, large semi-domes buttress the other two arches while also opening up the space below to accommodate the typical basilica floor plan.4

A panorama view of the domes from below. In the upper left corner can be seen the western semi-dome beneath which are two smaller semi-domes (over the exedrae) and between them an archway with window which looks out over the narthex. In the lower right corner can be seen the eastern semi-dome beneath which are two small semi-domes (over two other exedrae) and between them an archway that leads to the apse and its semi-dome.

Each of these two large semi-domes is exactly half the size of the central dome and rises to the central dome’s base (but no higher). For their own support they each have beneath them two smaller semi-domes over the exedrae (labeled on the floor plan above), flanking a central arch that leads to a separate element. To the east, the separate element is the apse of the sanctuary, and that has its own semi-dome extending beyond the square of the building (again, see the floor plan). To the west, the separate element is the narthex (and exonarthex); the archway between the exedrae houses a semicircle window above the narthex.5 From the west comes the light of this world, and from the east comes the light of the other world. The otherworldly light is represented by the mosaic in the apse, typical of Orthodox Churches, of the Mother of God and Christ Child. For the apse is the cave where the Son of God becomes incarnate in the mystery of communion.

These meanings reflect the floor plan below, typical of the Christian basilica, dividing the church sequentially into narthex, nave, and sanctuary. This horizontal, rectilinear hierarchy of the base, inherited from tabernacle and temple worship of the Old Testament and referencing the threefold pattern of the spiritual life (purification, illumination, and perfection)6, is essential to the meaning of the church; it is its foundation, its floor, its body. But this article must focus primarily on the domes, the soul — the vertical hierarchy.

To contemplate the meaning of the semi-domes beneath the central dome, I would refer again to this space as the soul of the building. But first a word should be said about how I view this symbolism happening. It’s hardly likely that Anthemius of Tralles and Isidore of Miletus, when they were designing the cathedral, were deliberately guiding their work by symbolic ideas. I assume they were merely thinking intuitively about the beauty of architectural forms while diligently calculating the engineering necessary to keep the walls and ceiling from collapsing. It’s like when the builders of the Pantheon mixed the cement with heavy rock at the bottom of the dome, and gradually lighter rock as they ascended, until porous volcanic rock was used at the top — they for sure were not thinking like symbolists who just read about the statue in Nebuchadnezzar’s dream in the Book of Daniel. They were just responding to how their materials behaved while creating something their souls recognized as beautiful. Anthemius and Isidore were doing the same. But in the age of Justinian, how they recognized beauty was formed by a deeply Christian culture. So if the patterns of the architecture they designed could have mapped onto them the patterns of how the Church fathers thought the human soul was structured, it wouldn’t exactly be a coincidence.

For the imperial Church of the time (all of Hellenic culture, really) had a certain understanding of the soul — quite different from our culture’s materialist psychology. Helpfully, the tripartite structure of these semi-domes conforms to its pattern.

The semi-dome on the east side of the building. The exedrae are on the left and right.
In the middle is the archway that leads to the apse.

According to the ancient Greeks, the soul is tripartite. Plato famously described it as a winged charioteer guiding two winged steeds.7 This image is enshrined in the Church’s prayer, too. An Ode I irmos in tone 4 recurring in canons of the Octoechos and Menaion reads (in part), “Drown Thou, I pray Thee, the three parts of my soul in the depths of dispassion, as of old Thou didst drown the mounted captains of Pharaoh.”8 The mounted captain is

(1) the rational aspect — the logikon or logos (reason), which has primacy — primacy, that is, over the two steeds, or lower aspects:

(2) the incensive faculty, the thymikon or thymos, the seat of repulsion in the soul, often characterized as anger; and

(3) the appetitive faculty, the epithymētikon or epithymia, the seat of attraction in the soul, often characterized as desire.

The idea as here expressed comes from Greek philosophy (Plato and everyone after), but it taps into something very simple in the natural law, the understanding of which Church fathers (none more so than St. Maximus the Confessor9) could root in Scriptural revelation all the same. Simply put, the soul is passible but has agency. As if penetrated by a magnetic field, it naturally pulls in and pushes out; but by the volitional power of reason, it can sort and guide these processes. (Jonathan Pageau has many times described a pattern just like this appearing in iconography, pertaining to virtually whenever an image has a center, right, and left.10)

Taken together, I think the two sets of semi-domes with exedrae match the pattern of this understanding of the soul contemporary with the building and still accessible in the tradition of the Church. The larger, superior part pairs with the rational faculty, and the two smaller parts beneath it on its right and left pair with the appetitive faculty and the incensive faculty.

Their west-east bifurcation, moreover, could be matched with the different ways our tripartite soul participates in the practical and contemplative aspects of theotic life. Making a distinction between praxis (practice) and theoria (contemplation) has been a habit of Western thought since ancient Athens, renewed in latter days by the likes of Kant and Marx (for whom theoria was more like theory). The case is no different with the Church fathers relevant here. In Ambiguum 10.1, St. Maximus the Confessor writes, quoting Nemesius of Emesa’s On the Nature of Man 41,

Those who have made a careful study of human nature say that the faculty of reason has two aspects: the “contemplative and the practical.” The “contemplative aspect is the power of the intellect to understand what pertains to beings, whereas the practical is the deliberative power [to bouleutikon] that determines the right use of reason for those engaged in practice.”11

Thus there is a sense that,

(1) in the practical aspect of theosis, the logikon aspires (utilizing volition), the thymikon strives (repelling obstacles), and the epithymētikon desires (has appetite); whereas

(2) in the contemplative aspect of theosis, the epithymētikon conjectures (gaping for truth), the thymikon has conviction (repelling falsehood), and the logikon apprehends (mediating noesis with the soul).12

And so the tripartite soul as experienced through practical and contemplative life can be shown to conform to the same pattern exhibited in Hagia Sophia’s intermediate structure of bifurcated, tripartite semi-domes. Concerning praxis and theoria, as Lars Thunberg notes when discussing St. Maximus’s Ad Thalassium 3, “Here we notice clearly that the two kinds of function go together, though the contemplative function is the higher, since it concerns the divine light of mystical knowledge, while the ‘practical mind’ carries the virtues which are natural to man.”13 Hence the semi-domes to the west, with their window over the narthex, match with praxis, while the semi-domes to the east, with their archway to the apse, match with theoria. In the act of contemplating forms, all this pairing can be called symbolism, or it could be described simply as the recognition of patterns. It is after this fashion of contemplation that a church comes to be a microcosmos, or a macroanthropos, fractally resonating with the theology, cosmology, and anthropology of those under its roof.

But if Hagia Sophia is to be contemplated as a macroanthropos, we have some steps left to make before completing the image. The primary part of the tripartite soul was identified by Plato as the logos. When in the fourth century Evagrius appropriated the pattern, however, he mostly identified the nous instead of the logos at the top of the lower passions. This is a subtle distinction but not without meaning. St. Maximus, as part of his cleansing of the Evagrian tradition from its Origenism, correctly divided soul and spirit (cf. Heb. 4:12), identifying the logos as the chief aspect of the tripartite soul and locating the entire tripartite structure in an intermediate position between the senses below and the nous above.14

When other Church Fathers, especially earlier ones, use the more biblical language of body, soul, and spirit to describe man, they are following a similar pattern but with different words. The spirit and nous alike are the highest part of the soul, the point of potential contact with that which is above. The logos, meanwhile, is the highest part of the soul in its mediation of the soul’s lower aspects and ability to orient them towards that which is higher. Relevant to what we’ll discuss next, St. Gregory Palamas in his 150 Chapters integrates the different teachings on mind, logos, and spirit to present a singular trinitarian image in man of the single trinitarian God — Mind, Logos, and Spirit.15

One of the four seraphim decorating the four pendentives beneath the main dome of Hagia Sophia.
(Source: Wikimedia Commons)

The Pendentives

The pendentive structure joining the arches beneath the dome performs a similar integrating function. Physically, it transforms the squareness of the arches into the circularity needed to support the dome’s base. Symbolically, the pendentives take the whole hierarchy of hemispheres in the building’s interior and draw them into one ocular opening at the apex. The adjacent semi-domes may symbolize the logikon (the rational faculty), and they may rise to the same height. But the pendentives symbolize the top of the soul as spirit. And just like the six-winged seraphim which are typically depicted on these structures (and can be clearly seen on them in Hagia Sophia since a 2009 restoration) — what they behold above them is something else. Open thy mouth wide, and I will fill it.

(Source: Wikimedia Commons)

As can be seen in the diagram above, the pendentives (labeled a) take the shape of a hemisphere but with its sides lopped off by the four arches, yielding four triangular shapes. This nearly dematerialized hemisphere joining the semi-domes ultimately symbolizes exactly what the dome of the Pantheon does. The Pantheon gives us a temple with an interior sphere that rises to a singular ocular opening at the apex of the building. That oculus is only 27 feet wide. Here it is blown open to 108 feet as it receives a visitor from above. I am the Lord thy God… Open thy mouth wide, and I will fill it.

Image by Florian Wizorek.

There is a dome under the dome of Hagia Sophia. It is its soul. The top of this soul is one but is contemplated threefold. The semi-domes taken together are logos. The pendentives drawing all space upward are spirit. And the oculus that is its mouth is its mind, its nous.16

The oculus of Hagia Sophia is the circular rim the pendentives form. The oculus is not the apex of the building. The oculus should never be the object of one’s worship. It is rather the means of one’s worship. The apex should be something else. But it is beyond our control whether it should join itself to our building or not.

I am the Lord thy God who led thee out of the land of Egypt. Open thy mouth wide, and I will fill it.

Image by Florian Wizorek.

The Dome

The dome is the incarnate Word of God. Typically Christ Pantocrator is depicted iconographically in the central dome of Orthodox churches. That may have been the case here, too (or it may have been a Cross; we don’t know); regardless, the architectural meaning abides. The dome symbolizes the nature of God joined to the nature of man in the singular Person of the Word. Atop the Pantheon the oculus was an empty, narrow hole. Here the oculus is blown open and filled with God made visible.

Maintaining an image of this union in one’s personal life is difficult for us sinners (to put it mildly). Architecturally achieving an image of this union likewise does not have an uninterrupted history. The current dome is not the original dome built hastily in the 530s — astonishingly the entire construction of Hagia Sophia was accomplished in just six years — but a replacement built in 562. A series of earthquakes starting in 553 (a mere couple of months after the Fifth Ecumenical Council, second of Constantinople) first left cracks in the main dome and eastern semi-dome before a quake in 558 brought them down, destroying the altar and sanctuary and causing stress damage throughout the building. Repairs and reconstruction began immediately, overseen by Isidore the Younger, nephew to the original designer. (Isidore of Miletus and Anthemius of Tralles had not lived to see the collapse.)

Though built taller and with lighter materials, the new 562 dome (the design of which survives to this day, though parts have had to be replaced due to more earthquakes) maintained the symbolic meaning of the original. Especially notable are the forty windows along the base, notches between radial ribs extending from the center. Creating a ring of light around the base of the dome reminds the viewer below that the rim of the pendentives is the equivalent of the Pantheon’s light-filled oculus and that the dome above it is a revelation of something new. It also, visually, makes the dome appear weightless, as if the God above is alighting upon creation not out of the necessity of gravity but as an act of absolute free will, an act of love. There is also a sense, theologically, that God is light, and that God is darkness. The ring of light around the lower perimeter symbolizes God as light, a kataphatic expression of God as He can be participated in, but behind it is a form that blocks the sunlight. It is divine darkness, an apophatic expression of the impenetrability of God’s essence, even if the light-tipped radii of God’s energies are made known.

I remember being a catechumen, before I attended any lectures in Morse Auditorium, and first hearing about Hagia Sophia from my parish priest, who spoke of it with awe. I remember being convinced from that moment that it was the greatest building in the world. Every single thing I’ve learned about it since has just been another flying buttress stacked against that presumption.17

The next part of the article, on the onion dome, will be published next Friday.

The Plan of the Article:

α. it began as Temple Israel
              β. dome on a box
                             χ. the risk of collapse
              ο. hemispherical interior
ω. God, heaven, and earth

                             Β. THE PANTHEON, ROME
                             α. the cosmos separate from God
                                            β. the rectangular portico
                                                           χ. the dome and oculus
                                            ο. oculus as mind
                             ω. Christian conversion

                                                           Ξ. HAGIA SOPHIA, CONSTANTINOPLE
                                                           ς. the semi-domes
                                                                          ζ. the pendentives
                                                                                         η. the dome

α. history and practicality
              β. frame and surface
                             ξ. the Cross
ο. tip as paradise
              ω. potential for inversion

                             Ω. BRUNELLESCHI’S DOME, FLORENCE
                             α. a giant hole to fill
                                            β. self-supporting walls
                                                           ξ. oculus complete
                             ο. the lantern
                                            ω. ambiguity and judgment

This article is currently being edited and will be reposted soon

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  1. I call this kind of structure a “ksiasmus.” It is related to the chiasmus, but whereas chiasmus is named after the Greek letter chi (Χ) because of its inverse parallel structure, a ksiasmus has a direct parallel structure and so is named after the Greek letter ksi (Ξ). It is a form not uncommonly found in Scripture. An easy example to point to is the arrangement of the camps of Israel around the tabernacle in Numbers 2. They are listed in the following order: east camp, south camp, central camp, west camp, north camp.
  2. I will only be covering the top layer of buttress support in the original design. Many buttresses have since had to be added all around the bottom of the building. See Architecture News, “Architectural Adventure of Hagia Sophia,” for models of changes to Hagia Sophia through the years. The image in the text above this footnote is from that site.
  3. Hagia Sophia is built on a northwest-southeast axis. For simplicity I refer to the sanctuary side as the east and the narthex side as the west, for these are their symbolic functions. Physically the sanctuary apse is in the southeast, and the rectangular narthex and exonarthex are in the northwest. The massive external piers which together with the semi-domes support the central arches are physically on the northeast and southwest sides of the building — or the symbolic north and south.
  4. See the especially helpful animated models in Nova, “Hagia Sophia: Istanbul’s Ancient Mystery,” at 6:35 and at 18:32.
  5. In the gallery a floor above the narthex is the empress’ lodge, where the empress would attend services facing directly opposite the apse in the front in which is depicted the Mother of God and Christ child.
  6. See Maximus Confessor, Selected Writings (Paulist Press, 1985), pp. 189–90. This citation is from The Ecclesiastical Mystagogy, where St. Maximus does not offer a contemplation of the narthex. For him the nave proposes ethical philosophy (or purification), the sanctuary spiritually interprets natural contemplation (or illumination), and the altar manifests mystical theology (or perfection). I think this interpretation maps also onto a narthex-nave-sanctuary triad in that each element looks for its purpose in what is superior to it. Thus the purification (of the narthex) is the nave, the illumination (of the nave) is the sanctuary, and the perfection (of the sanctuary) is the altar.
  7. See Plato, Phaedrus 246.
  8. See, e.g., The Octoechos, Volume II (The St. John of Kronstadt Press, 2007), pp. 96, 140, and 142.
  9. For an overview, see Lars Thunberg, Microcosm and Mediator (Open Court, 1995), pp. 174–207. St. Maximus spent his early adulthood working in the imperial court at Constantinople. One could easily speculate that the structure of Hagia Sophia (not yet a hundred years old then) was an important influence on his thought.
  10. See for example the four articles linked under the heading “The Left and Right Side in Christian Art” on Pageau’s media and writings page,
  11. Maximos the Confessor, On Difficulties in the Church Fathers, Volume I (Harvard University Press, 2014), p. 157.
  12. This contemplation is in part a product of John Wild’s reading of Plato viewed by me through a Maximian lens. See John Wild, Plato’s Theory of Man (Harvard University Press, 1946), pp. 148–58.
  13. Thunberg, Microcosm, p. 340.
  14. See Thunberg, Microcosm, pp. 197–98, where he cites a number of relevant passages in St. Maximus’s Ad Thalassium.
  15. Chapters 34–40. See The Philokalia, Volume IV (Faber and Faber, 1995), pp. 359–64. The idea is not original to him; see Maximos the Confessor, On Difficulties, Volume I, p. 111.
  16. St. Maximus contemplates nous as mouth at Ad Thalassium 65.5. See St. Maximos the Confessor, On Difficulties in Sacred Scripture: The Responses to Thalassios (The Catholic University of America Press, 2018), p. 522.
  17. Although the Nova video previously mentioned (see footnote 4) has the most useful information about the physical structure, my favorite Hagia Sophia video I’ve seen on the internet is this wordless walkthrough posted by the channel Istanbul and Food in 2019:

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