The land walls of İstanbul cross the historic peninsula for about seven kilometres, from the Marble Tower on the Sea of Marmara to the Golden Horn. They went up in the fifth century under Theodosius II, the Eastern Roman emperor whose name they still bear, and they lie inside the city's UNESCO World Heritage area. Today the line can be followed past restored gates and a long public park, with the fortress of Yedikule at one point and, near Edirnekapı, a Byzantine palace and a church famous for its mosaics.
How the defences worked
The strength of the walls lay in depth rather than height alone. An attacker from the west had to cross a moat and climb a lower outer wall before even reaching the main wall behind it; taken together, this system is about 70 metres across. The inner wall had 96 towers, most of them square, and they were spaced to suit the ground instead of at regular intervals.
A typical tower held two rooms with no link between them. The lower one opened on the city side and served as a store, while the upper one was reached from the wall-walk and had windows for watching and shooting. The builders faced everything in cut limestone and ran bands of brick through it, tying the stone skin to the mortar core so that the masonry could ride out earthquakes.
Earthquakes, Attila and sixty days
Those bands were needed. Earthquakes in 437 and 447 hit the line hard, and the second brought down long sections and 57 towers just as Attila's armies were in the Balkans. Theodosius II gave the prefect Constantine the job of rebuilding. Byzantine chroniclers and three inscriptions on site say the work took sixty days, with the chariot-racing teams of the city supplying labour.
Inscriptions naming emperors and officials record repair after repair in the centuries that followed. After the Latin conquest of 1204 upkeep slipped, and by the sieges of 1422 and 1453 there were too few defenders to man both lines, so they concentrated on the outer wall. The walls then lasted through the whole Ottoman period, and foreign travellers kept writing about them.
The gates to look for
Gates are where the line is easiest to understand. Belgradkapı, between towers 22 and 23 near Yedikule, appears in Eastern Roman sources as the Xylokerkos Gate, the wooden circus, and is thought to have been the main entrance before the Golden Gate existed. After the conquest people called it the Closed Gate, and it remained sealed through much of Ottoman rule until 1886, when it was reopened, partly to give access to the Balıklı Greek Hospital. Two explanations are given for its present name: the neighbourhood behind it, or people from Belgrade settled here in the 16th century. An earthquake in 1894 took the upper parts of its towers, and the gate was restored in 1986-1987 by İstanbul Metropolitan Municipality and the Taç Foundation.
The Golden Gate, further south, was the ceremonial way in. This was where the Via Egnatia arrived from Thrace, and emperors entered here at the head of triumphal processions, continuing along the Mese, the main street, to the Augustaion in front of Hagia Sophia. The name comes from gilded doors added following a victory in 425, and statues above it once included a Nike and an elephant-drawn chariot.
Yedikule, the fortress on the walls
Behind the Golden Gate the Byzantines had already built a five-towered stronghold, which Bayezid I forced John V to demolish in 1391 by threatening his son Manuel, then an Ottoman captive. Mehmed II went further after the conquest. Three new towers were added in the late 1450s, and four older Byzantine towers brought the total to seven, yedi kule in Turkish, hence the name.
Under the Ottomans it housed a garrison, the imperial treasury until Murad III moved it to the palace, and state prisoners held in two of the towers. The Janissaries killed the young sultan Osman II here in 1622, and the Genç Osman Tower takes its name from the room where he died. Yedikule became a museum in 1895. Fatih Municipality took it over in 2020 and began restoration, clearing rubble and uncovering Roman and Ottoman paving and the foundations of the Fatih Mescidi; some 16,000 square metres inside the walls were turned into an open-air museum and event space.
Near Edirnekapı
Two sights close to the walls are worth adding. Tekfur Sarayı at Edirnekapı is the surviving part of the Blachernae Palace complex, three floors squeezed between the land walls and an earlier wall. It later became a tile workshop: when it was decided in 1718-19 to make tiles in İstanbul, production was set up in its courtyard, and the work is still known by the palace's name. It now holds a museum on that subject. About a hundred metres from the walls stands the Kariye Mosque, once the Chora church of the Holy Saviour and the surviving centre of a large monastery, known for its mosaics and frescoes. It opened for worship on 6 May 2024.
The walls now
İBB Miras, the heritage team of the metropolitan municipality, began in 2020 on a restoration it presents as the most extensive the walls have had. It calls the approach archaeological restoration: a site keeps the look of a ruin, and intervention stops at what structural safety requires. Mevlanakapı, Edirnekapı, Sulukulekapı and the hypogeum at Silivrikapı have all been treated this way. A visitor centre at Mevlanakapı came first, in September 2022, and Belgradkapı followed with its own centre and a reference library added on 24 February 2024.
Fatih Municipality has also laid out the Karasurları Millet Bahçesi beside the line, a public park that was built in stages, running past Mevlanakapı and Silivrikapı from Millet Caddesi down to Belgradkapı. Its fourth stage is the grounds of Yedikule, so the park and the fortress can be seen as one long walk beside the walls.
