Istanbul: A City Written and Rewritten by Empires

Istanbul is a city that later empires wrote over earlier ones without erasing them, and the clearest way to read it is to cross water. The old Sultanahmet peninsula stacks Roman, Byzantine, and Ottoman capitals onto one small headland where the Bosphorus, the Golden Horn, and the Sea of Marmara meet. Across the Golden Horn, a Genoese hill grew into the merchant, banking, and European Istanbul that faced west and lived by plurality. And down along the market quarter between the two seas, the commerce that paid for every dome ran downhill from covered vaults to the water. Three walks, three registers of the same argument: this is a layered city, and you learn to read it by watching who built onto what.

Start with the peninsula, because Sultanahmet holds the grammar the rest of the city repeats. On the Peninsula of Empires walk, Hagia Sophia is the whole idea compressed into one shell. It was completed as a cathedral in 537 under the emperor Justinian the First, its architects Anthemius of Tralles and Isidore of Miletus floating an enormous dome on four curved triangles of masonry so the roof seems to hover on a ring of light. It served as an Orthodox cathedral until 1453, became a mosque after the Ottoman conquest, opened as a museum from 1935, and was reconverted to a working mosque in 2020. Four lives in one building, nothing fully erased. That is the lesson you carry to every other stop.

The peninsula: three capitals on one headland

The layers on the peninsula are literal, and often below your feet. The long public square of Sultanahmet is the oldest layer of all: it was the Hippodrome, a Roman chariot circus first raised around the year 203 when Septimius Severus rebuilt Byzantium, then greatly enlarged after Constantine the Great refounded the city as Constantinople in 324. The track is gone, but three monuments Constantine and his successors gathered still stand in pits below today's pavement, including the Obelisk of Theodosius, an Egyptian obelisk of the pharaoh Thutmose the Third re-erected here in 390. Across the square, the Blue Mosque answers Hagia Sophia directly. Built for Sultan Ahmed the First and completed in 1616 by the architect Sedefkar Mehmed Aga, its cascade of domes and more than twenty thousand blue Iznik tiles are a deliberate reply to the cathedral facing it. Two empires holding a conversation across one square.

The reuse runs underground too. The Basilica Cistern, built in the sixth century under Justinian, rests its ceiling on about three hundred and thirty-six marble columns, most of them spolia salvaged from older Roman buildings, and in one corner two carved Medusa heads serve as column bases, one on its side and one upside down. Their meaning was discarded along with their original home. The peninsula walk ends at Little Hagia Sophia, the church of Saints Sergius and Bacchus built around 527 to 536, converted to a mosque under Bayezid the Second and still working today. The great cathedral's church-to-mosque story, told again in a quieter key. And near Hagia Sophia stands the Column of Constantine, raised to mark the dedication of the new capital on the eleventh of May, 330, beside the fragment of the Milion, the Byzantine zero-mile marker from which every distance in the empire was measured. This is the true center the whole city was built around.

The city across the water: the plural hill

Cross the Golden Horn and the register changes completely. The City Across the Water walk climbs the hill the postcards leave out. The Genoese established a self-governing merchant colony at Galata in 1267, answering to Genoa rather than to the emperor opposite, and in 1348 they rebuilt the tower at the summit of their walls, calling it the Christea Turris, the Tower of Christ. It rises about sixty-three metres, and from its square you can look south to the peninsula of domes and then turn to face the other Istanbul behind you.

That other Istanbul was built on money and mixture. Bankalar Caddesi, Banks Street, was the financial center of the late Ottoman Empire, home to the Ottoman Stock Exchange established in 1866 and the Ottoman Bank building completed in 1892 by the architect Alexandre Vallaury. The curving Camondo Stairs, built around 1870 to 1880, were commissioned by Abraham Salomon Camondo of a Sephardic Jewish banking dynasty, and were later photographed by Henri Cartier-Bresson in 1964. A short walk away, the Church of Saint Anthony of Padua, built between 1906 and 1912 and the largest Roman Catholic church in Istanbul, anchors a quarter that held Greek Orthodox and Armenian churches, synagogues, and mosques within a few streets of each other. The future Pope John the Twenty-third, then the priest Angelo Roncalli, preached here for about ten years as the Vatican's envoy to Turkey.

This hill was European in its engineering as well as its faiths. The Tunel, opened on the seventeenth of January, 1875, is the second-oldest underground urban railway in the world after the London Underground, conceived by the French engineer Eugene-Henri Gavand and chartered by Sultan Abdulaziz. And a quieter layer coexisted with all of it: the Galata Mevlevi Lodge, founded in 1491 during the reign of Bayezid the Second, where whirling dervishes of the Mevlevi order performed the sema. The walk resolves at Taksim Square and the Republic Monument, unveiled in 1928 and sculpted by the Italian artist Pietro Canonica, where the cosmopolitan Ottoman hill hands over to the Turkish Republic founded in 1923.

The bazaar between two seas: the engine underneath

If the peninsula is the crown and Galata is the plural hill, the market quarter is the machine that funded both. The Bazaar Between Two Seas walk holds one idea the whole way down: every dome on the skyline was paid for by the market below it. The Grand Bazaar began with a single decision, when Mehmed the Second established it in the winter of 1455, just two years after taking the city, raising the inner stone jewellers' hall, the Cevahir Bedesten, at its heart. From that core it grew into sixty-one covered streets holding roughly three thousand to four thousand shops. Behind the glitter, the hans, courtyard caravanserais like the Buyuk Valide Han commissioned in 1651 by Kosem Valide Sultan, still ring with coppersmiths at work.

The endowment logic is made explicit on the third hill. The Suleymaniye Mosque, built between 1550 and 1557 by the imperial architect Mimar Sinan for Suleyman the Magnificent, is the largest Ottoman-era mosque in the city, but it was never only a mosque. Sinan laid out a kulliye around it: colleges, a hospital, a medical school, and a public soup kitchen, all funded by rents from the surrounding shops. The grandeur up top was underwritten by the trade below. Sinan repeats the trick at the Rustem Pasha Mosque, commissioned in 1562 and raised on a terrace over vaulted shops whose rents help support it, its interior sheathed in roughly two thousand three hundred Iznik tiles. The walk ends at the water, at the Spice Bazaar built in the years after 1660 with the tax revenues of Ottoman Egypt (its Turkish name, Misir Carsisi, means Egyptian Bazaar), and the New Mosque above the Eminonu ferry docks, completed around 1663 by Turhan Hatice Sultan. This is where the money came in by boat and moved up the hill and back down again.

Read together, the three walks make one point. Istanbul is not a set of separate postcards but a single system that rebuilt itself in place: empires stacked on the peninsula, a plural merchant city on the hill across the water, and a market between the two seas that paid for all of it. Learn the grammar at Hagia Sophia, and you will see the layers everywhere. To plan a route through all three, start with the Istanbul walking tours hub.

Sources

• UNESCO World Heritage Centre, Historic Areas of Istanbul (inscribed 1985), whc.unesco.org/en/list/356
• Encyclopaedia Britannica, Hagia Sophia, britannica.com/topic/Hagia-Sophia
• Encyclopaedia Britannica, Grand Bazaar and Ottoman architecture entries, britannica.com
• Roamer tour transcripts for The Peninsula of Empires, The City Across the Water, and Bazaar Between Two Seas (fact-audited source content)
• Istanbul Metropolitan Municipality cultural heritage pages on the Galata Tower, the Tunel funicular, and the Grand and Spice Bazaars