By the mid-15th century, Constantinople was hemmed in by Ottoman-controlled territories. On May 29, 1453, after a seven-week siege, the Turks launched a final assault. Bursting through the city's defenses and overwhelming its outnumbered defenders, the invaders poured into the streets, sacking churches and palaces, and cutting down anyone who stood in their way. Terrified citizens flocked to Hagia Sophia, hoping that its sacred precincts would protect them, praying desperately that, as an ancient prophesied, an avenging angel would hurtle down to smite the invaders before they reached the great church.
Instead, the sultan's janissaries battered through the great wood-and-bronze doors, bloody swords in hand, bringing an end to an empire that had endured for 1,123 years. "The scene must have been horrific, like the Devil entering heaven," says Crowley. "The church was meant to embody heaven on earth, and here were these aliens in turbans and robes, smashing tombs, scattering bones, hacking up icons for their golden frames. Imagine appalling mayhem, screaming wives being ripped from the arms of their husbands, children torn from parents, and then chained and sold into slavery. For the Byzantines, it was the end of the world." Memory of the catastrophe haunted the Greeks for centuries. Many clung to the legend that the priests who were performing services that day had disappeared into Hagia Sophia's walls and would someday reappear, restored to life in a reborn Greek empire.
That same afternoon, Constantinople's new overlord, Sultan Mehmet II, rode triumphantly to the shattered doors of Hagia Sophia. Mehmet was one of the great figures of his age. As ruthless as he was cultivated, the 21-year-old conqueror spoke at least four languages, including Greek, Turkish, Persian and Arabic, as well as some Latin. He was an admirer of European culture and patronized Italian artists, such as the Venetian master Gentile Bellini, who painted him as a bearded, introspective figure swathed in an enormous robe, his small eyes gazing reflectively over an aristocratically arched nose. "He was ambitious, superstitious, very cruel, very intelligent, paranoid and obsessed with world domination," says Crowley. "His role models were Alexander the Great and Julius Caesar. He saw himself as coming not to destroy the empire, but to become the new Roman emperor." Later, he would cast medallions that proclaimed him, in Latin, "Imperator Mundi"—"Emperor of the World."
Before entering the church, Mehmet bent down to scoop up a fistful of earth, pouring it over his head to symbolize his abasement before God. Hagia Sophia was the physical embodiment of imperial power: now it was his. He declared that it was to be protected and was immediately to become a mosque. Calling for an imam to recite the call to prayer, he strode through the handful of terrified Greeks who had not already been carted off to slavery, offering mercy to some. Mehmet then climbed onto the altar and bowed down to pray.
Among Christians elsewhere, reports that Byzantium had fallen sparked widespread anxiety that Europe would be overrun by a wave of militant Islam. "It was a 9/11 moment," says Crowley. "People wept in the streets of Rome. There was mass panic. People long afterward remembered exactly where they were when they heard the news." The "terrible Turk," a slur popularized in diatribes disseminated across Europe by the newly invented printing press, soon became a synonym for savagery.
In fact, the Turks treated Hagia Sophia with honor. In contrast to other churches that had been seized and converted into mosques, the conquerors refrained from changing its name, merely adapting it to the Turkish spelling. ("Ayasofya" is the way it is written in Turkey today.) Mehmet, says Ilber Ortayli, director of the Topkapi Palace Museum, the former residence of the Ottoman emperors, "was a man of the Renaissance, an intellectual. He was not a fanatic. He recognized Hagia Sophia's greatness and he saved it."
Remarkably, the sultan allowed several of the finest Christian mosaics to remain, including the Virgin Mary and images of the seraphs, which he considered to be guardian spirits of the city. Under subsequent regimes, however, more orthodox sultans would be less tolerant. Eventually, all of the figurative mosaics were plastered over. Where Christ's visage had once gazed out from the dome, Koranic verses in Arabic proclaimed: "In the name of God the merciful and pitiful, God is the light of heaven and earth."
Until 1934, Muslim calls to prayer resounded from Hagia Sophia's four minarets—added after Mehmet's conquest. In that year, Turkey's first president, Kemal Ataturk, secularized Hagia Sophia as part of his revolutionary campaign to westernize Turkey. An agnostic, Ataturk ordered Islamic madrassas (religious schools) closed; banned the veil; and gave women the vote—making Turkey the first Muslim country to do so. He cracked down harshly on once-powerful religious orders. "Fellow countrymen," he warned, "you must realize that the Turkish Republic cannot be the country of sheikhs or dervishes. If we want to be men, we must carry out the dictates of civilization. We draw our strength from civilization, scholarship and science and are guided by them. We do not accept anything else." Of Hagia Sophia he declared: "This should be a monument for all civilization." It thus became the world's first mosque to be turned into a museum. Says Ortayli, "At the time, this was an act of radical humanism."
Although ethnic Greeks constituted a sizable proportion of Istanbul's population well into the 20th century, the heritage of Byzantium was virtually expunged from history, first by Mehmet's Ottoman successors, then by a secular Turkey trying to foster Turkish nationalism. Nobel Prize- winning author Orhan Pamuk says that by the 1960s, Hagia Sophia had become a remnant of an unimaginably distant age. "As for the Byzantines," he writes in his memoir, Istanbul, "they had vanished into thin air soon after the conquest, or so I'd been led to believe. No one had told me that it was their grandchildren's grandchildren's grandchildren who now ran the shoe stores, patisseries, and haberdasheries of Beyoglu," a center-city neigborhood.
Turkish authorities have made little effort to excavate and protect the vestiges of Byzantium (apart from Hagia Sophia and a handful of other sites) that lie buried beneath modern Istanbul. The city's growth from a population of 1 million in the 1950s to 12 million today has created development pressures that preservationists are ill equipped to resist. Robert Ousterhout, an architectural historian at the University of Pennsylvania, has worked on Byzantine sites in Turkey since the 1980s; he was once awakened in the middle of the night by work crews surreptitiously demolishing a sixth-century Byzantine wall behind his house to make room for a new parking lot. "This is happening all over old Istanbul," says Ousterhout. "There are laws, but there's no enforcement. Byzantine Istanbul is literally disappearing day by day and month by month."