People have lived on this peninsula since at least 6000 BC, when rising sea levels may have flooded the Bosphorus strait and first separated Europe from Asia here. The Greek colony of Byzantium proved so strategically valuable that it fell, in succession, to the Persians, the Spartans, the Athenians, and finally the Romans in 196 AD. What followed was not conquest but transformation. Emperor Constantine, recognizing what the oracle had implied centuries earlier, proclaimed the city his eastern Imperial capital in 330 AD. He fortified the peninsula with walls. In the 5th century, Emperor Theodosius pushed those walls further west, enclosing the entire ridge — and sealing in what would become the most fought-over real estate in European history. The Byzantine Empire based here outlasted the fall of Rome by a full thousand years, its citizens all the while calling themselves Romans. By the 15th century, the empire had shrunk to little more than this peninsula. After a 55-day siege, on 29 May 1453, the Ottoman dynasty breached the Theodosian Walls and ended a civilization.

Stand in Sultanahmet Square today and you are standing inside the old hippodrome — or rather, two meters above it. The track is gone, the stands are gone, but you can still trace the U-shaped curve where chariots once hurtled around in the colors of the Greens and the Blues, rival political factions that commanded the loyalties of the city's mob. The first hippodrome dates to 203 AD; Constantine rebuilt it grander in 324. In 532, a dispute between the factions became the Nika Riots, a catastrophe that left 30,000 dead and half the city in ruins. From those ruins came Hagia Sophia — construction began that same year, 532, and the great basilica was completed in 537, on ground cleared by the disaster. The ancient monuments still punctuate the square: a pair of obelisks, the bronze stump of the Serpent Column, and at the north end the ornate German Fountain of 1901, Kaiser Wilhelm's gift to Sultan Abdülhamid II in exchange for approval of the Berlin-Baghdad railway project. The Crusaders looted the hippodrome in 1204 and the races never resumed.

Before there were palaces and mosques, there were cisterns and aqueducts. The Valens Aqueduct, completed in 368 AD, vaults double-storied across the valley on 921 surviving meters of Roman brickwork, drawing water from sources 120 kilometers west in the mountains of Thrace. The Basilica Cistern beneath the streets once held enough water to supply the entire city through a siege. Engineers were as essential to Byzantine survival as soldiers. When the Ottomans arrived they did not tear everything down — they converted, adapted, and built atop. Churches became mosques. The Topkapı Palace grew across the site of the original Greek colony on the ridge above Gülhane Park. The Sublime Porte, the gatehouse that became shorthand for Ottoman imperial power itself, anchored the edge of that compound. What the visitor sees today is not one civilization but several, each built on the rubble and bones of what came before, each leaving its mark on the same ridge above the same blue water.

After 1453, the Ottomans set about making the city fit for a sultan and his empire. They tore down Christian imagery and converted the great churches — Hagia Sophia first among them — into mosques. Then they built their own monuments: Sultanahmet (the Blue) Mosque, completed in 1616, its six minarets a deliberate provocation to rival Mecca; the Grand Bazaar, still trading; the hamams that served a city where almost no household had running water. Suleiman the Magnificent commissioned the Süleymaniye Mosque on the ridge above the Golden Horn, and the great architect Mimar Sinan built it so that its cascading domes seem to flow down the hillside toward the water. When the empire finally collapsed in the early 20th century and Atatürk moved the capital to Ankara in 1923, this peninsula became something it had never quite been before: a place defined by its past rather than its power. The tourists who had begun arriving by VW camper in the 1960s already understood that.

The Historical Peninsula is compact enough to walk, hilly enough to remind you of its age. The ridge is said to have seven hills — a claim made, the Wikivoyage guide notes tartly, mainly to assert the old city's equality with Rome. Sultanahmet at the tip is the obvious starting point: a one-kilometer strip containing Topkapı Palace, Hagia Sophia Mosque, the Blue Mosque, and a cluster of museums that could absorb a week. The ancient Middle Street, now Divan Yolu ("state council road"), descends west from those heights, closed to vehicles, lined with tea houses and carpet sellers. Tram T1 traces the same route. Further out toward the Theodosian Walls, the streets empty and the stones get older: the Column of Marcian from around 450 AD, still standing on Kızanlık Caddesi; the Chora Church mosaics glowing in the northwest corner; the walls themselves, still mostly intact despite every army that tried to knock them down. The peninsula rewards wandering. The Milion stone — Mile Zero of the Eastern Roman Empire, from which all distances were once reckoned — survives as a scrap of column on Divanyolu Caddesi, easy to miss, worth finding.