Who Built the Hagia Sophia?

The Hagia Sophia — the Church of Holy Wisdom, Sancta Sophia in Latin, Ayia Sofia in modern Turkish — was built in Constantinople between 532 and 537 CE under the direction of the Byzantine emperor Justinian I. The architects were the mathematicians Anthemius of Tralles and Isidore of Miletus, the two greatest geometric theorists of the early sixth century, and the construction was carried out by an army of thousands of skilled craftsmen and laborers. When the church was dedicated on 27 December 537, it was the largest cathedral in Christendom and would remain so for nearly a thousand years. Justinian is said to have exclaimed, on entering the completed building, “Solomon, I have surpassed you!”

The building of the cathedral cannot be understood apart from the Nika riots that destroyed its predecessor, the reign of Justinian that funded it, and the broader history of the Byzantine Empire.

The Setting

The Hagia Sophia was built on the site of an earlier church of the same name, the first great cathedral of Constantinople, which had been dedicated by Constantine I in 360 (or 415, after reconstruction) and had been destroyed in the Nika riots of January 532. The site, in the heart of the imperial city, was the natural location for the principal church of the eastern Roman Empire, and the imperial family had long had a particular interest in its construction. Justinian’s decision to rebuild on a much grander scale was, in part, a response to the political crisis of the Nika riots: the new Hagia Sophia was meant to be a physical and symbolic demonstration of the emperor’s authority, an architectural proclamation that the imperial state was not only intact but had been transformed.

The architects Anthemius of Tralles and Isidore of Miletus were chosen for their mathematical skills, not for their experience in architecture. Anthemius was a Greek from the Anatolian city of Tralles, the author of a treatise on burning mirrors and a specialist in geometry; Isidore was a Greek from Miletus, the author of a commentary on ancient mathematics. Both were university professors in Constantinople, and both had been summoned by Justinian to assist in the reconstruction of the city. The decision to use mathematicians as architects was deliberate: the engineering problems of the new Hagia Sophia — the construction of a vast dome over a square base — were unprecedented, and the emperor wanted the leading mathematicians of the day to design the building.

The Design and Construction

The Hagia Sophia was designed as a centralized building of unprecedented scale. The plan, broadly speaking, was a rectangle about 100 meters long and 70 meters wide, with a vast central nave covered by a shallow dome, two half-domes on the eastern and western sides, and two lower aisles on the north and south. The dome, about 31 meters in diameter and rising to about 55 meters above the floor, was the largest in the world when the building was completed and would remain so until the construction of the dome of Florence Cathedral in the fifteenth century. The dome was supported on four great pendentives — curved triangular sections of masonry that resolved the geometry of the circular dome base into the square of the supporting piers — and on two half-domes. The result was a building of staggering internal volume, with the dome appearing to float above the worshippers below.

The construction was carried out with extraordinary speed. The foundations were laid in February 532, the walls were rising in 533, and the dome was being built in 535 and 536. The workforce included 5,000 workers on each side of the building (according to the chronicler Agathias), supervised by ten foremen. The materials were drawn from all over the empire: the white marble came from the quarries of Proconnesus in the Sea of Marmara, the purple porphyry came from Mons Porphyrites in the Egyptian desert, the green marble came from Karystos in Euboea, the black marble came from the Bosphorus region, the gold and silver came from the imperial treasury, and the rest of the building was constructed of brick and mortar. The columns of the nave, 107 in number, were largely taken from older Roman buildings, including the temple of Artemis at Ephesus (one of the wonders of the ancient world).

The dome itself was constructed of light, porous brick, with the joints between the bricks laid in a special mortar made of lime and pumice. The architects were aware that the dome would settle, and they allowed for a small initial flattening at the top; they may also have provided for a system of internal buttressing that was concealed by the half-domes. The dome was originally completed in 537, but an earthquake in 558 caused a partial collapse, and the dome was rebuilt to a slightly different design by the younger Isidore, the nephew of the original Isidore. The current dome, completed in 562, is the Isidore the Younger’s version.

The Interior Decoration

The interior of the Hagia Sophia was originally decorated in a manner of unparalleled richness. The walls were sheathed in marble revetments, the vaults and domes were covered in gold-ground mosaics, the floors were paved with marble, and the building glittered with the imperial purple and gold. The original figurative mosaics, which would have included the imperial family, Christ, the Virgin, and the saints, were lost during the iconoclast period of the eighth and ninth centuries, when figurative images were banned. The post-iconoclast mosaics, of which the most famous are the great Deësis panel of Christ flanked by the Virgin and John the Baptist, the apse mosaic of the enthroned Virgin and Child, and the imperial panels commemorating the Macedonian dynasty, all date from the ninth to the thirteenth centuries.

The original liturgical furniture of the Hagia Sophia was also of imperial scale: a great ambo, a silver altar screen (templon, later iconostasis), a throne for the patriarch, and an imperial box (kathisma) connected to the imperial palace. The relics of the True Cross, the Crown of Thorns, the Lance of Longinus, and many other Christian relics were housed in the church, and pilgrims came from all over the Christian world to venerate them. The Hagia Sophia was, in the words of the historian Procopius, “the most beautiful building in the world,” and it remained so for the rest of the Middle Ages.

The Building’s Cultural Role

The Hagia Sophia was the cathedral of the patriarch of Constantinople, the site of the emperor’s coronation, the venue of the great liturgical ceremonies of the Orthodox Church, and the physical symbol of the eastern Roman state. It was the model for an enormous number of other churches across the Byzantine world and beyond: the church of Hagia Sophia in Thessalonica, the cathedral of St. Sophia in Kiev, the cathedral of the Dormition in Vladimir, the great church of the Monreale in Sicily, and the Hagia Sophia of Trebizond, all show the influence of the Justinianic building. The image of the Hagia Sophia, in plan, in elevation, and in iconography, became the standard for the Orthodox Christian church.

The Hagia Sophia was also a center of imperial ceremony. The emperor appeared in the imperial box during the liturgical services; the patriarch presided over the liturgy; the imperial family was buried in the church; the relics of the saints were housed in the side chapels. The building was, in effect, the religious and political heart of the empire, and it served as a stage for the great events of Byzantine public life.

After the Byzantine Empire

The Hagia Sophia remained a Christian cathedral for almost a thousand years after its dedication, serving as the cathedral of the patriarch of Constantinople through the iconoclast controversy, the Macedonian renaissance, and the late Byzantine centuries. After the Ottoman conquest of Constantinople in 1453, the building was converted into a mosque, and the minarets of the Ottoman mosque were added around the building. The mosaics were covered with whitewash in accordance with Islamic practice, but many survived and have been uncovered in modern times. In 1934 the Turkish Republic declared the building a museum, and the mosaics have been gradually restored. In 2020 the building was re-converted into a mosque, although it remains open to visitors.

The Hagia Sophia continues to stand, more than 1,500 years after its construction, as one of the most significant buildings in the history of architecture: the masterpiece of Byzantine architecture, the cathedral of the Orthodox Church for nearly a millennium, and a symbol of the surviving Roman state in the medieval Mediterranean. The artistic tradition that the Hagia Sophia represented is treated in early Christian and Byzantine art.