Inside a municipal cafe built into Istanbul’s ancient city walls, waiters scurried back and forth carrying cups of strong Turkish tea and hefty slices of chocolate cake. On one side of the modern wooden building, the view opened towards the Bosphorus, on the other was a courtyard formed from the towering limestone and brick ramparts once built to defend the entire city from invaders, now welcoming people for a hot drink, and a view of a playground. The waiter Adem Bulgan pointed to a section of the ancient structure next to a walkway, one that bore deep concave marks of erosion. “See, it’s crumbling – it’s a historical artefact and it’s crumbling,” he said. The wonder of spending the day within a centuries-old structure had quickly worn thin and repairs could be a drag, he added. Occasionally, pieces fell off, requiring a call to municipal officials rather than staff being allowed to fix it themselves. Despite restoration led by the opposition-controlled Istanbul municipality, local news stories about sections of the wall collapsing are a frequent occurrence, a sign of how the city’s pre-Ottoman heritage often hides in plain sight, is allowed to wither or is obscured for political purposes. Local architects and historians grumbled when a Byzantine palace was restored – under a former Istanbul mayor loyal to President Recep Tayyip Erdoğan – to emphasise its Ottoman features, and is now a museum displaying Ottoman-era crafts. Zeynep Ahunbay is an antiques scholar and restoration expert with a long record of work on the land and sea walls that symbolise the protection of the former capital of the Byzantine empire. She said the current mayor, Ekrem İmamoğlu, was interested in protecting the walls, but this was expensive. “Maybe that is the reason for the restricted action, in comparison to the works carried out on Ottoman heritage, which are supported by the central government,” she said drily. İmamoğlu’s administration has also frequently tussled with public sentiment over whether to destroy the prized Yedikule urban gardens that date to the Byzantine era as part of their potential restoration project. The desire to use walls to shield this coveted stretch of land next to the Bosphorus Strait from potential invaders originates from the reign of the emperor Constantine the Great, who made the eastern Roman city, then known as Byzantium, his capital in 330, renaming it Constantinople. The double-layered thick stone ramparts that are visible today date from the fifth century, and are called the Theodosian walls, after the Byzantine emperor Theodosius II, who oversaw their construction. They span around 6.5km (4 miles), marking the ancient borders that the city has long since outgrown. Large sections of the Byzantine walls, as well as other ancient remains, dot an area of Istanbul known as its historical peninsula, now the conservative municipality of Fatih. The choice of whether to preserve them or simply build modern constructions around them is often a private one. At a carpet and pottery shop carefully built on top of a sixth-century cistern that may have once served the Great Palace of Constantinople, a salesman called Nihad said he sometimes wandered downstairs to have a coffee before work. “It’s like time travel to the sixth century,” he said. A restaurant manager, Şükrü Golak, said of the mosaics, stonework and artefacts found underneath modern hotels across the peninsula: “Below us is a different city. It smells of Rome, Byzantium – and the Ottomans.” In a courtyard shaded by the mulberry and pomegranate trees that decorate the Cretan restaurant where he has worked for almost three decades, Golak pointed to an outer wall that he and some of the restaurant’s historian regulars believe dates from the Byzantine era. “There’s weeds growing out of it – it’s difficult to maintain, but at least it’s not crumbling. It’s in better condition than most,” he said. “Not many places have something like this, and we want to protect it.” For Golak, offering people the chance to eat dinner next to a piece of ancient history is a draw for customers. “Our guests come here to touch the wall – and touch history,” he said. When Constantine XI stood on top of the city walls in 1453 in a failed effort to defend the beleaguered Byzantine capital from a more technologically advanced Ottoman army, his forces were outnumbered and outgunned – particularly by the cannon that blew holes in the walls intended to protect against invasion. Today, the walls symbolise a turning point in the city’s history and that of the wider region: the conquest of Istanbul by Ottoman Sultan Mehmed II, marking the end of the Byzantine empire. Constantinople became the capital of the Ottoman empire, renamed Istanbul, and many churches and cathedrals, including the famed Hagia Sophia, were converted into mosques. The government in Ankara has long sought to harness this symbolism. The day after Erdoğan’s re-election earlier this year, the then-interior minister, Süleyman Soylu, marked the 570th anniversary of the Ottoman conquest by praying at the Hagia Sophia, which Erdoğan’s administration proudly converted back into a mosque after decades as a museum. Alexander Christie-Miller, the author of the forthcoming To the City: Life and Death Along the Ancient Walls of Istanbul, pointed to a museum dedicated to the Ottoman conquest that lies close to the crumbling walls, while the site of the conquest itself has long been overlooked. “It’s ironic that there’s a completely artificial recreation of the siege, but 200 metres away from the actual scene where it happened is in a state of massive neglect – there’s obviously an element of this connected to a longstanding strain in republican Turkish history whereby the pre-Ottoman heritage is neglected,” he said. This neglect, combined with the ability to hide from public view between the double walls which run along some underserved neighbourhoods of Istanbul, has led to pockets being heavily associated with crime. In 2016, Fatih police arrested an accused drug lord who had kidnapped and tortured a Syrian couple, and hid them as well as himself in a cavity converted into an expansive living space within the walls. “The walls have always been this area where, just through their sheer size and the amount of ground they cover, are outside neighbourhood control, a no-man’s land. It’s really a function of their size, and that Istanbul as a city has never had the capacity to really restore them,” said Christie-Miller. One of the main tasks of the Byzantine state, he added, was to maintain the walls. “The walls were there to protect the city from annihilation, and there was a civic need to maintain them, as a symbol of preservation and survival. What’s amazing is that the walls are still standing, still relatively intact, but they feel so disconnected from modern life in Turkey and what’s around them.” Byzantine history The Byzantine empire was the name given to the eastern part of the Roman empire, in reference to the ancient Greek city of Byzantium, which became the empire’s capital in 330AD and was renamed Constantinople. While what remained of the western portion of the Roman empire dissolved, the Byzantine empire ruled for another thousand years. The Ottomans were Turkic warriors originating in Anatolia around 1300, who began fighting the remnants of the Byzantine empire. The conquest of Istanbul in 1453 marked the end of the Byzantine empire, and the rise of the Ottomans, whose empire spanned swaths of north Africa, the Arabian peninsula, modern day Turkey and Iraq and up into the Caucasus at its peak. The empire lasted 600 years, until the overthrow of the last Ottoman sultan in 1922, followed by the foundation of the Turkish republic in 1923.