Houses of worship shape the rites, even the faith, of the congregations who gather within them. Solomon’s temple in Jerusalem is an obvious example. With its construction, the Divine Presence moved from a tent in a rural shrine into a grand temple adjacent to the royal palace, where God was worshipped with the pageantry befitting the royal court. Henceforth, Jewish sacrificial worship became increasingly centralized in Jerusalem.

The Church of Haghia Sophia in Istanbul, Turkey has likewise had a lasting impact on faith and worship. It is often simply called “the Great Church” because of its grandeur and its important role in the Byzantine Christianity.

An engineering marvel of late antiquity, Haghia Sophia stood unsurpassed in size and splendor for a thousand years. Even today it dominates the skyline of modern Istanbul -formerly Constantinople – which from 330 to 1453 was the capital of the Eastern Roman, or Byzantine, Empire. Time has faded Haghia Sophia’s splendor, but not diminished the majestic soar of its arches and domes.

After Constantine I defeated his rivals for the Roman throne (c. 324), he accepted the Christian faith, which he credited for his victory. In 328, Constantine began to move his government to the East, to the Greek town of Byzantium, which he renamed Constantinople, the city of Constantine.

In an effort to stress the Christian nature of the new Rome, Constantine began constructing a number of churches, the most important being the Church of Haghia Sophia, Greek for “Holy Wisdom,” for it is dedicated to Christ, “the Wisdom of God.”

Constantine’s church was rebuilt by the Emperor Theodosius II in the mid-fifth century, after it was destroyed during riots that broke out in 404 when the patriarch, John Chrysostom, was sent into exile. Theodosius’s church was also destroyed by riots (532) during the reign of Emperor Justinian I (527-565).

There could not have been a better time than the reign of Justinian for a church to need rebuilding. Justinian walked in the company of great ruler-builders of the ancient world: Solomon, Herod, Constantine. Driven by a complex mix of piety and pride, Justinian built or rebuilt churches throughout the empire, including the Church of the Nativity in Bethlehem and 34 churches in Constantinople itself. Justinian resolved to rebuild Haghia Sophia as the greatest church on earth. He succeeded; it would be a millennium before St. Peter’s in Rome would provide a worthy rival.

Justinian employed two masters who were mathematicians as well as architects, Anthemius of Tralles and Isidore of Miletus, and told them to “disregard all questions of expense.” Their mathematical skills were put to the test, for they set out to resolve on a grand scale the challenge of supporting a round dome on a rectangular base. Anthemius and Isidore used only the common structural materials of the time – chiefly brick – for the walls, buttresses and dome of the building, but they fashioned them into an architectural masterpiece, as a virtuoso might play an exquisite sonata on an ordinary fiddle.

More than 10,000 workers labored five years, ten months and four days to build Haghia Sophia. Its central worship area measures 107 by 250 feet; with its side aisles, Haghia Sophia covers more ground than two football fields. Yet its grandeur lies not in its expanse but in its height. Supported by an ingenious system of half domes, arches and pendentives (concave, triangular spaces that support the dome over a square base, perhaps invented by Anthemius and Isidore), a great dome 107 feet in diameter soars 180 feet above the floor of the church, crowning the worship area. Forty arched windows ring the base of the dome as portals of light, making the dome seem to “float in the air” and “be suspended from heaven,” in the words of Procopius, the court historian who chronicled Justinian’s reign.

The interior of the church was furnished as befitting the grandeur of its plan, “disregarding all questions of its expense” and nearly bankrupting the imperial treasury.

Paul the Silentiary, a court poet, wrote a Homeric epic of 887 hexameters describing the church and its furnishings. He lists emerald marble from Sparta, green marble from Carystus, black marble from the Bosporus, yellow marble from Libya and other hues from other quarries. The altar was a slab of gold inlaid with precious stones, supported by four gold columns; behind it hung a curtain sewn with a half a million pearls. Twenty tons of silver were used in the inner sanctuary alone.

The new Haghia Sophia was dedicated on 27 December 537. Prior to the dedication, Justinian walked into the church and exclaimed “Glory be to God, who has thought me worthy to finish this work! Solomon, I have surpassed thee!”

Probably taking his cue from Justinian, Procopius praises Haghia Sophia with words befitting Solomon’s temple:

“Whenever anyone enters this church to pray, he understands at once that it is not by any human power or skill, but by the influence of God that this church has been so wonderfully built. His mind is lifted up towards God and exalted, feeling that God cannot be far away, but must especially love to dwell in this place which he has chosen.”

The outpouring of an empire’s wealth upon a church bespeaks not merely the religious devotion and pride of achievement of an emperor in erecting monuments, but also the intricate relationship between church and state. While church and state were not identified with each other, neither were they completely separate realities. To be a member of the church was to be a citizen of the empire, and to be a citizen was to be a Christian.

Bishop Eusebius of Caesarea, Constantine’s advisor and biographer, had characterized the emperor as the elect of God, ruling as his viceregent and representative on earth, responsible for the spiritual as well as the political welfare of his people. Byzantine emperors did not hesitate to convene church councils when religious differences threatened the unity of their empire.

Justinian built Haghia Sophia to be the patriarchal church, but equally to be the imperial church, the gathering place where Justinian and his court would worship. When the emperor attended liturgy, both state and church were at prayer.

Justinian left a legacy in Haghia Sophia that has left a lasting impact on Eastern Christianity. The dome of Haghia Sophia is more than an engineering marvel; it is also rich in liturgical meaning. This begins to emerge when we contrast it with another ancient church design, the basilica.

Today the word “basilica” is a title of honor for certain church buildings, but in Roman times it was a secular term, describing an oblong building with a central hall, or nave, and two or more side aisles. These aisles were separated from the nave by a row of columns that supported a wall of windows and a timber roof. Basilica-style buildings were used for various civic functions. A semicircular apse added to one end provided a place for governors to preside over public functions, or a place for judges to sit when holding court.

Constantine’s great Church of the Martyrium, built adjacent to Calvary and the tomb of Jesus in Jerusalem and dedicated in 335 A.D., was built in the basilica manner, as were many later large churches. But the basilica broke up the worshiping congregation with pillars and spread them out along a long nave, separated from the clergy in the apse.

If a basilica disperses and separates, a domed building gathers. The dome of Haghia Sophia is so broad and lofty that everyone within the worship area feels bound in an embrace. It binds the congregation together, as a body of the faithful gathered for worship, corporately offering the divine liturgy. The Rev. Louis Bouyer, the pioneering liturgical scholar, notes that the plan of Haghia Sophia may be the “best adaptation” of architecture to liturgy, the “most successful attempt” in the ancient church to fashion a building for worship.

In time, the dome of Haghia Sophia took on additional liturgical significance. Eastern Christians came to see the dome of Haghia Sophia, and later the countless others that were copied from the Great Church, as a symbol of heaven. Originally the dome and upper parts of the church were covered with gold mosaic; later a mosaic bust of Christ the Pantocrator, or Righteous Judge, filled the dome. Four-winged cherubim were depicted in mosaic in the pendentives supporting the dome, and below them mosaics of apostles and saints were added in the course of time. The tiny glass tesserae of the mosaics were fractionally tilted to reflect light from windows and lamps.

Liturgy on earth was a participation in the liturgy of heaven. The congregation, surrounded by mosaics and icons of those who had gone before them, marked with the sign of faith, joined with the whole company of heaven in adoring God. The church building was not simply a place to gather together, but was itself a sign of what took place in the divine liturgy.

Haghia Sophia, with its soaring dome, shimmering mosaics and elegant furnishings, was a powerful proclamation of earthly liturgy as participation in the heavenly liturgy. This is reflected in the Chronicle of Nestor, a work that describes the conversion of the Rus’ (the ancestors of modem Belarussians, Russians and Ukrainians) to Christianity. Prince Vladimir of Kiev sent representatives to examine the religions of the kingdoms around him, in order to decide what would be his state religion. In the course of their travels Vladimir’s representatives visited Constantinople. As Nestor’s Chronicle tells it:

“The emperor of Constantinople sent a message to the patriarch to inform him that a delegation had arrived to examine the Greek Christian faith, and directed him to prepare the Church of Haghia Sophia and the clergy, and to array himself in his sacerdotal robes, so that the Rus’ might behold the glory of the God of the Greeks.

“When the patriarch received these commands, he bade the clergy assemble, and they performed the customary rites. They burned incense and the choirs sang hymns. The emperor accompanied the Rus’ to the church, and placed them in a wide space, calling their attention to the beauty of the edifice, the chanting, the pontifical services and the ministry of the deacons, while he explained to them the worship of his God.”

In their report back to Vladimir, the delegates said that they had seen the Germans “performing many ceremonies in their temples, but we beheld no glory there. Then we went to Constantinople and the Greeks led us to the edifices where they worship their God, and we knew not whether we were in heaven or on earth. For on earth there is no such splendor or such beauty, and we are at a loss how to describe it. We only know that God dwells there among men.”

Vladimir and his people accepted baptism in 988, the event celebrated in 1988 as the 1,000th anniversary of the conversion of the Rus’ to Byzantine Christianity.

Even if the account of the Chronicle of Nestor is, as some judge, apocryphal, it does capture the spirit of the Eastern liturgy, particularly when celebrated in great churches like the Haghia Sophia. Eastern liturgy involves worship with all the senses: chant for the cars, incense for the nose, bread and wine for the tongue, standing and bowing for the body and beauty for the eyes – particularly the beauty of icons, “windows onto the sacred.”

Haghia Sophia was not the first domed church, and the liturgy celebrated in Constantinople had antecedents in the liturgies of Syria and Jerusalem. But the influence of the liturgy as celebrated in the Haghia Sophia on the worship of the Eastern Church was profound. It was not that Constantinople legislated imitation; rather, the magnificence and prestige of the liturgy celebrated in “the Great Church” meant that it was widely imitated. Not only did the liturgies of St. John Chrysostom and St. Basil that were celebrated in Haghia Sophia become the norm, but also Haghia Sophia’s style of celebration, a style of profound solemnity. What had its origin in a fellowship meal shared in a guest room in Jerusalem evolved into a solemn liturgy befitting emperors and patriarchs.

Although its influence endures, time has taken its toll on the Great Church. It has been repeatedly rocked by earthquakes, and its dome had to be rebuilt even during the lifetime of Justinian. Haghia Sophia was sacked by Crusaders in 1204 and witnessed the sorry spectacle of Western Christians despoiling Christendom’s greatest church. After the Turks conquered Constantinople in 1453, Haghia Sophia was converted into a mosque. Its mosaics were plastered over and minarets were added to its exterior.

The loss of Haghia Sophia as a place of Christian worship was tragic, but its conversion into a mosque was, in one sense, providential. As a mosque it was preserved from destruction during five centuries of Ottoman rule; as a church it would have been more vulnerable. Even the plastering over of mosaics may have been a preservative blessing in disguise.

Ironically, Haghia Sophia as a mosque influenced Islamic worship just as it had influenced Christian worship. The great domed mosques found in Istanbul and throughout the nations of the former Ottoman Empire echo the architecture of Haghia Sophia; it was the theme upon which Muslim architects composed their variations.

After the demise of the Ottoman Empire, Kemal Ataturk created the secular state of Turkey. In 1935, because of the historic significance of Haghia Sophia to both Christians and Muslims, he converted it into a museum, opening the edifice to the general public. Most of its Christian mosaics have been uncovered and restored.

Those who visit Haghia Sophia today enter a building heavy with faded glory, but dappled with exquisite beauty. In a side gallery there are the remains of a magnificent mosaic, the Deesis: a sensitively drawn Christ blesses the viewer, while the Virgin Mary and John the Baptist intercede, presumably on our behalf. In the apse, a solemn image of the Virgin, seated with the Christ Child on her lap, gazes down at the thousands of people who now enter the museum. When Pope Paul VI visited the church in 1967, it has been reported that, overwhelmed with emotion, he knelt in prayer when he first saw this stunning image. It was the first public demonstration of Christian prayer in Haghia Sophia since 1453.

Islamic calligraphy jostles against Christian iconography: an inscription from the Qur’an now fills the center of the dome, surrounded by Byzantine cherubim. There is too much to take in, yet the geometry of the building demands that it be seen as a whole, drawing one’s eyes up to the great dome. One must stand and gaze, move to a new vantage point and gaze, move again and gaze again.

And in one’s gazing almost inevitably the thought occurs: Oh, to be standing here 1,000 years ago, while patriarch and emperor were at worship under the dome of heaven, with incense filling the air and chant echoing off marble and the light of a thousand lamps shimmering in mosaics. Oh, to be part of that earthly anticipation of the liturgy of heaven that led Vladimir’s emissaries to exclaim, “We knew not whether we were in heaven or on earth; we only know that God dwells there among men.”

Even today, even after the vicissitudes of 15 centuries, Haghia Sophia still deserves its title, “the Great Church.”

George Martin frequently contributes to these pages.