Hagia Sophia's Four Lives: How One Building Teaches You to Read Istanbul

Hagia Sophia compresses the entire history of the Sultanahmet peninsula into one building. It has been a cathedral, a mosque, a museum, and a mosque again, and across every change of use most of the structure survived. That single fact, that each empire on this headland built onto what it found rather than sweeping it away, is the grammar of the whole walk. Learn to read it here, standing under the dome, and you will read it everywhere else on the old peninsula.

The building that keeps its receipts

Hagia Sophia was completed as a cathedral in five hundred and thirty-seven, under the emperor Justinian the First. It went up fast: about five years and ten months, with a workforce of more than ten thousand. Its architects, Anthemius of Tralles and Isidore of Miletus, floated an enormous dome on four curved triangles of masonry, so the roof seems to hover on a ring of light. For nearly a thousand years it was the largest cathedral in the world. The current dome is not even the first. After an earthquake in five hundred and fifty-eight brought the original down, Isidore the Younger rebuilt it roughly twenty Byzantine feet higher, giving the interior a height of about fifty-five and a half metres.

Then read the sequence of its uses soberly, because it is the point. It was an Orthodox cathedral until the Ottoman conquest of fourteen fifty-three, with a Catholic interlude during the Latin Empire from twelve oh four to twelve sixty-one. After the conquest it became a mosque, and slender minarets rose at its corners. From nineteen thirty-five it was a museum, open to Christian mosaic and Islamic calligraphy at once. In twenty twenty it was reconverted to a working mosque, which is what it is today. UNESCO inscribed it as part of the Historic Areas of Istanbul in nineteen eighty-five. Four lives in one shell, nothing fully erased. Once you can see that, you have the key to the peninsula.

Rome underneath the square

Carry the idea a few hundred metres and it starts paying off immediately. The long open square beside the mosques is the Hippodrome, a Roman chariot-racing circus. The first version rose around the year two hundred and three, when Septimius Severus rebuilt old Byzantium, and Constantine the Great greatly enlarged it after refounding the city as Constantinople in three hundred and twenty-four. At its height it ran roughly four hundred and fifty metres long and held something like one hundred thousand spectators. In five hundred and thirty-two the crowd here rose in the Nika riots that nearly toppled Justinian.

The track is gone, but the trophies Constantine and his successors gathered still stand, and they sit in pits below today's pavement. That gap is the literal depth of Rome. The Obelisk of Theodosius is an ancient Egyptian monument of the pharaoh Thutmose the Third, carved more than three thousand years ago and re-erected here in three hundred and ninety. The Serpent Column was cast from the melted weapons of a defeated Persian army after the Battle of Plataea in four hundred and seventy-nine B C, and stood at Delphi before Constantine moved it here. This is the same reuse you read at Hagia Sophia, only now you are looking down instead of up.

The Ottoman reply, and a cistern of borrowed columns

Across the square from the old cathedral, two great domed buildings face each other. The second is the Sultan Ahmed Mosque, the Blue Mosque, laid down in sixteen hundred and nine and completed in sixteen sixteen. Its architect, Sedefkar Mehmed Aga, worked in the tradition of the great Sinan, and the silhouette is a deliberate answer to Hagia Sophia across the way: a central dome buttressed by four half-domes that cascade into smaller domes, with six minarets marking the corners. The upper walls carry more than twenty thousand blue Iznik tiles in over fifty designs. A major restoration completed in twenty twenty-three. Stand between the two buildings and you are watching two empires hold a conversation across one square.

Then the walk goes underground, into the Basilica Cistern, built in the sixth century under Justinian to store water for the palace above. Its roof rests on about three hundred and thirty-six marble columns, and here the layering turns explicit: most of them are spolia, reused pieces salvaged from older Roman buildings. In one corner, two carved Medusa heads serve as column bases, one set sideways and one completely upside down, with no inscription to explain them. They were almost certainly convenient blocks taken from some earlier structure, their meaning discarded along with their original home. That is the whole peninsula in one gesture: the past reused, turned sideways, and kept.

The gate, the zero point, and the quiet echo

The route reaches Seraglio Point, where Topkapi Palace was built beginning around fourteen fifty-nine, only six years after the conquest, under Mehmed the Second. For roughly four hundred years it was the sultans' home and the seat of government, until the court moved away in eighteen fifty-six; it became a museum in nineteen twenty-four. Power here moved inward, court by court, from the public square you crossed toward this guarded point above three seas.

Two street monuments hold the true center. The Column of Constantine, known in Turkish as Cemberlitas, marks the dedication of the city on the eleventh of May, three hundred and thirty, and is the oldest surviving Constantinian monument still standing in Istanbul. Nearby, the fragment of the Milion was the Byzantine zero-mile marker, the point from which every distance in the empire was measured. One monument says the city was founded here. The other says the world was measured from here.

The walk ends softly at Little Hagia Sophia, once the Byzantine church of Saints Sergius and Bacchus, built under Justinian around five hundred and twenty-seven to five hundred and thirty-six, a few years before the great cathedral was finished. Its dome is divided into sixteen curving compartments. Under the Ottomans it became a mosque, around fifteen oh six to fifteen thirteen, and it remains one today. The same grammar, told quietly: church, then mosque, one empire building on the last.

Seven stops, about four and a half kilometres, roughly two hours of walking. It is a cluster on one small headland, so you can reorder or skip stops and still hold the thread. Read the layers rather than racing to see everything. Start at Hagia Sophia, learn the grammar, and let the rest of the peninsula fall into place. Browse more Istanbul walking tours, or see what else is on offer in Istanbul.

Sources

• Hagia Sophia, Wikipedia: construction dates, architects, the dome rebuild, and the cathedral-mosque-museum-mosque sequence.
• Hippodrome of Constantinople and Serpent Column, Wikipedia: Roman arena history, the Obelisk of Theodosius, and the Plataea trophy.
• Basilica Cistern, Wikipedia: the sixth-century reservoir, its reused columns, and the Medusa-head bases.
• Column of Constantine and Milion, Wikipedia: the founding column of three hundred and thirty and the Byzantine zero-mile marker.
• UNESCO World Heritage, Historic Areas of Istanbul: the nineteen eighty-five inscription covering these monuments.