1. General introduction

Hagia Sophia or simply "Megale Ekklesia" (the Great Church) was the cathedral of Constantinople, erected in the center of the Constantinian city on the First Hill, very close to the Great Palace and the Hippodrome. Adjoined to the somewhat earlier church of Hagia Eirene, with which it shared the same enclosure, and together with the Hospice of Samson, they formed a large complex administered by the same clergy.¹ The present building (now Ayasofya Müzesi), erected by the Emperor Justinian I in the early sixth century, is the third church of Hagia Sophia at the site. The first Hagia Sophia, built in the second half of the 4^th century and known simply as the Great Church, and the second, 5^th-c. building were both destroyed by fires in the course of riots in Constantinople.

2. The Great Church in the fourth and fifth century

The plan of the first two churches is unknown but it is reasonable to assume that they were timber-roof, three-aisled or five-aisled basilicas. The first Hagia Sophia was consecrated in 360 in the reign of Constantine´s son Constantius II.² It burned together with the neigbouring Senate during the 404 riot and was perhaps first repaired by the Emperor Arcadius and then built anew or thoroughly reconstructed by Theodosius II (the inauguration of the church in 415).³ The only part that survived the fire was a circular building adjacent to the church; this may have been the same as the still standing skeuophylakion at the north-east corner of Hagia Sophia.⁴ The bread and wine for the liturgy in Hagia Sophia were prepared in the skeuophilakion, and gold and silver chalices, patens, gospel books and liturgical vessels were also stored there. In addition, written sources also enumerates a considerable number of precious relics that were kept in this building.⁵ The liturgical vessels and the relics were probably stored in rectangular round-headed niches that articulate the interior of the building on two levels (the upper niches accessible from a corbelled gallery to which an external staircase led).⁶ Other remains of the pre-Justinianic church were found in front of the narthex: The colonnade with a mosaic floor excavated before the World War II belonged to the monumental gabled propyleum that preceded the atrium of Theodosius´s cathedral.⁷

3. Sixth-century cathedral

The damage of Theodosius´ cathedral during the Nika Riot in 532 was the great opportunity for Justinian to build a church that surpassed all ecclesiastical structures not only in the city but also in the whole Roman and post-Roman world. Anthemios of Tralles and Isidore of Miletus were employed as master-builders, and it is clear that they approached the design of the church from a theoretical perspective, disregarding the constraints of empirical building practice. The construction progressed rapidly and the new church, a colossal domed basilica with an apse projecting to the east and with a total lenght about 135 m, was inaugurated on 27 December 537. The daring construction of the first dome and the fact that the church was erected with haste led to the collapse of the dome after the earthquakes of 557.⁸ Unfortunately, Procopius does not describe the the original dome in detail.⁹ On the other hand, it is clear from Agathias´ account of the rebuilding of the church that the original dome was larger and lower than the second dome which was constructed by Isidore the Younger, nephew of the original engineer: «It [ie. the new dome] 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.» The church was re-consecrated in 562.¹⁰ The dome of Hagia Sophia is slightly smaller than the dome of the Pantheon in Rome; it has a diameter of 31.87 m and a height from floor level of 55.60 m.

Hagia Sophia displays a radically innovative design, combining elements that had already emerged in Early Byzantine religious architecture (in the church of Sts Sergios and Bakchos, and maybe even in the church of St. Polyeuktos) but in an original way and on a vastly larger scale. The weight of the dome passes through the pendentives to four massive piers. Between them the dome seems to float upon four great arches of which the western and eastern ones are extended by half domes carried on smaller semidomed exedras. The central domed core of the church is flanked by aisles on the south and north sides and by two nartheces on the west side. Galleries above the aisles and the inner narthex were originally accessible by four spiral ramps adjoining the four corners of the church – now only that on the north-west corner is in use for this purpose.

4. Patriarchate and baptisteries

The palace of the Patriarchs was also reconstructed after the Nika Riot. It was situated at the south-west corner of Hagia Sophia and comprised a long, possibly two-storied, vaulted hall flanked by smaller rooms. Only the north wall (with three large round-headed, now blocked, openings) and part of east wall as well as springings of vaults remain of the large hall. These remains of the main reception space of the palace can be seen above the Ottoman ablution fountains.¹¹ There are further rooms once probably belonging to the Patriarchate. These are well preserved and are situated above the south-west vestibule of the church and on the top of the south-west access ramp. They are usually dated in the reign of Justin II and are decorated with figurative mosaics executed probably in the 9^th century. Although directly accessible from the gallery of Hagia Sophia, they are not open to tourists.¹²

The octagonal domed building (now one of the sultans´ mausolea), situated to the left when leaving Hagia Sophia through the south-west vestibul, may also have been originally part of the patriarchal palace. Its architecture and masonry point to the 6^th century and it is usually identified as a baptistery. Although it served this function probably as early as the 9^th- or 10^th century, it may have been originally built as a small recetion hall of the patriarchs or a chapel because Paul the Silentiary (later 6^th century) in his description of Hagia Sophia mentions a baptistery that was apparently north of the church, which is also confirmed by other post-sixth-century sources. The patriarchate was enlarged in the 7^th century when the Thomaites Hall was added by one of the patriarchs of this name (Thomas I, 607-610, or Thomas II, 667-669).¹³

5. Appearance of Justinian´s church after its first dedication in 537

Despite several additions and modifications made during its almost 1500 years long history Justinian´s Hagia Sophia retains in general much of its original appearance. Nevertheless, if we want to visualize the Great Church as it probably appeared in 537 it is above all necessary to remove four Turkish minarets and outer buttresses surrounding the church on all sides. The outer buttresses are to be dated in the middle and late Byzantine periods: The flying buttresses on the west façade and those in the middle of both long sides as well as the south-west buttress belong to the former group while more massive buttresses on the east side of the church to the latter group (built by Andronikos II Palaeologos).¹⁴

The silhouette of the church in 537 also differed from the present state as the dome was originally lower and its curvature was similar to that of the four pendentives marking the transition between the four big piers and the drum of the dome. The present dome rises about 6 m higher than the original one. Moreover, the interior of the church was brighter than it is today. Besides blocking some windows by adding the outer buttresses, the principal alteration of fenestration occured after the first dome collapsed and was rebuilt: on the walls beneath the south and north big arches supporting the dome, were in 537 larger windows than the present ones (these are even smaller than after the rebuilding during Justinian´s reign due to later, probably Ottoman, interventions).¹⁵ In addition, the south-west and north-west porches does not seem to be part of the original design – the former was created when the rooms opening off the south gallery and belonging to the patriarchate were built (which also included modification of the top of the south-west access ramp tower).¹⁶

The most important loss is the disappearance of the Justinianic atrium that preceded the church on the west. The atrium extended westwards from the outer narthex for about 42 m and its three sides opened into the courtyard through pairs of columns alternating with piers.¹⁷ In the centre of the atrium was an elaborated marble fountain. The atrium disappeared in the Ottoman period and the last columns and piers were demolished in 1870s. In addition Hagia Sophia was in the 6^th century surrounded by courtyards on all sides;¹⁸ only the patriarchate, the Great Baptistery (on the north flank) and the earlier skeuophylakion adjoined the cathedral. The facades of Hagia Sophia were neither plastered nor presented their brick masonry but they were faced with white Proconensian marble slabs.

6. Interior decoration

As far as the interior is concerned, the surfaces were sheathed with polychrome marbles (as they are today) and decorated with numerous crosses and ornamental designs on gold mosaic background (in the south-west spiral ramp, inaccessible to public, a preserved fresco cross may also belong to the Justinianic period).¹⁹ Such a simple decoration is understandable if we take into account the very short time in which the cathedral was erected (only five years!). Columns also present various kinds of coloured marbles and are the important feature of the whole appearance of the interior: on the groundfloor are columns of green Thessalian marble and re-used porphyry columns while green columns dominate on the galleries. The column shafts carry white marble capitals. The marbles of Hagia Sophia were much admired by Byzantines and Procopius adds: “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…”.²⁰ Sculptors from St. Polyeuktos - a church with most impressive sculptural decoration and a challenge to Justinian from its donor, Anicia Juliana - were probably employed on the decoration of Hagia Sophia; however, or maybe as a response to the challenge, they reintroduced in Hagia Sophia a more conservative style with less oriental motifs than in St. Polyeuktos, while they also introduced the intricate arched entablatures and capitals that became hallmarks of Early Byzantine metropolitan style. As the interior was better lighted in the 6^th century than today (larger windows, numerous oil lamps and candles) the visual effect of the colorfull decoration of the interior must have been more impressive.²¹

In addition, the presence of liturgical furnishings made the appearance of the broad nave and the apse much different from what one see today. In the apse was installed a synthronon of seven semicircular steps of which the topmost one was occupied with the seat of the patriarch on the axis. In front of the synthronon was a ciborium composed of four silver columns supporting an octagonal canopy. The altar table of the Great Church, made of gold embellished with semiprecious stones, stood under the canopy. A silk and gold embroidery decorated with images of Christ and the Apostles Peter and Paul covered the altar table. The bema (presbytery) occupied much of the area beneath the eastern half-dome and it was composed of marble parapet slabs and silver columns carrying an architrave. A raised pathway projected westwards from the bema and led to the ambo, a raised stand used for reading the Gospel or the Epistle. The ambo was constructed of marble and ivory and was accessible by two flights of stairs. The imperial metatorium, a screened-off place where the emperor stayed during a mass, was probably in the easternmost bay of the south aisle. On the other hand, the empress´s place was on the gallery, above the inner narthex.²²

7. Post-Justinianic mosaics

As already said, the Great Church of Justinian was decorated in non-figurative mosaics (crosses, acanthus rinceau, geometrical patterns). However, images of Christ and the saints may have started to appear in the church soon after Justinian´s death if later sources mentioning scenes from the New Testament comissioned under Justin II are to be believed. By the mid-eighth century figurative mosaics were present in Hagia Sophia because the iconoclastic patriarch Nicetas is said to have destroyed (mosaic) images of saints and Christ, decorating the church, in 768.²³

Nevertheless, the oldest surviving figurative mosaics in Hagia Sophia date in the period after Iconoclasm in 843. These include the Virgin Mary with Child and the Archangel Gabriel in the apse executed in the later years of Michael III´s reign (842-867) and four winged seraphim on the pendentives of the dome (only two of them are original, probably 9^th-c mosaics; the other two are painted copies). The dome of the church was decorated (probably) also in the 9^th century with a large image of the Pantocrator (in 562 there was only a large mosaic cross in the dome). The Pantocrator mosaic disappeared completely but, what is interesting, it was still visible in the early Ottoman period when Hagia Sophia had already served as a mosque. Other early mosaics, which survived only fragmentary, are in the rooms above the south-west porch and the top of the south-west access ramp tower. They depict Deesis as well as various saints. These rooms are not accessible to public which is also the case of the small cruciform chapel with fragments of mosaics that is situated on the top of the south-west outer buttress. All of these mosaics probably date in the tenth century at the latest.²⁴

Nevertheless, other surviving mosaics are in the main space of the church and can be seen by the visitors. A magnificent 10^th-c. mosaic in the tympanum over the door leading from the south-west porch into the inner narthex shows the Virgin Mary with Child seated on the throne and flanked by Constantine and Justinian who offer to him models of the city of Constantinople and of the church of Hagia Sophia, respectively. Approaching further the interior of the building, one can admire a mosaic over the Imperial door (the middle door from the narthex into the nave, reserved for the emperor) dating in the late 9^th- or early 10^th century. This probably represents the Emperor Leo VI performing proskynesis (falling on his knees as the act of his homage) in front of Christ on the throne. Christ holds an open book in which are the words: “Peace be unto you. I am the Light of the World”. Christ is accompanied by two busts in roundels showing the Virgin Mary and the Archangel Gabriel.

Further figurative mosaics are on the galleries. In the north gallery is a relatively small mosaic image of the Emperor Alexander (912-913), while in the south gallery three more mosaics have survived. Alexander is depicted as standing figure and wears imperial cloak and scarf, gem-studded carmine buskins and helmet-like crown. As far as the mosaics in the south gallery are concerned the Deesis is the largest and, on the other hand, the latest mosaic in Hagia Sophia. It dates in the late 13^th or 14^th century and shows the Mother of God and St. John the Baptist pleading with Christ in an act of intercession for the salvation of humans. In the east extremity of the south gallery are two imperial mosaics. The earlier of them shows Christ enthroned between the Emperor Constantine IX and the Empress Zoe. The 11^th-c. imperial couple is depicted frontally in formal dress, bearing gifts (scroll and money). It is probable that the figure of the emperor has originally shown one of Zoe´s earlier husbands (Romanos III or Michael IV) and was later changed into the portrait of Constantine IX. The latter of the imperial mosaics in the south gallery was comissioned under John II Comnenus in the early twelfth century. It is a portrait of him and his wife Irene flanking the Mother of God with Child and a side panel depicts their son Alexius. It is similar to the mosaic of Constantine IX and Zoe, though it is less naturalistic and more schematized. The last mosaics to be mentioned decorate the balustrade above the galleries, beneath the round-headed windows in the north and south large tympana. There are rows of mosaics of bishops (those well preserved include St. Ignatius of Constantinople, St. John Chrysostom and St. Ignatius Theophorus of Antioch) each holding a codex and making the gesture of blessing.²⁵

8. Influence of Justinian´s Hagia Sophia on religious buildings in the East and West

Justinian´s Great Church is regarded as the greatest achievement of the Byzantine architecture. However, the direct architectural influence of the 6^th-c. cathedral of Constantinople on later Byzantine churches was not as significant as one would expect. Its complex design and graundeur had been never repeated. On the contrary, later Byzantine churches were erected on a modest scale reflecting both the shortage of resources after the sixth century and the trend to create smaller religious communities. Nevertheless, a dome resting on four piers or columns – the main compositional element of Hagia Sophia – was adapted by the builders of those later churches (often of the cross-in-square plan). Moreover, Hagia Sophia´s influence can be seen also on a symbolic level – it was the powerful symbol of the Empire and the Orthodox Church. The Great Church of Constantinople was admired not only within the Empire but its fame spread outside its borders (Western Europe, Russia) and became a source of inspiration also for Ottoman architects. The architectural and/or symbolic influences of Hagia Sophia can be traced for example in St. Sophia in Kiev (11th century), Langobard St. Sophia in Benevento (8th century), Charlemagne´s church at Aachen (8th/9th century) or in Giuliano de Sangallo´s church of St. Maria at Prato (late 15th century; perhaps influenced by Cyriacus of Ancona´s drawings of Hagia Sophia at Constantinople).²⁶ However, the full impact of Justinian´s cathedral is more obvious in great Ottoman mosques such as Suleymaniye Camii and Sultanahmet Camii in Istanbul.