The Historic Areas of Istanbul are a UNESCO World Heritage Site made up of four protected zones on the Historic Peninsula, in the Fatih district of Istanbul, Turkey, between the Golden Horn, the Bosphorus and the Sea of Marmara. Inscribed in 1985 under cultural criteria (i) to (iv), the zones are the Sultanahmet Archaeological Park at the tip of the peninsula, with Hagia Sophia (537), the Sultan Ahmed or Blue Mosque (1609–1617) and Topkapı Palace (begun 1459); the Süleymaniye quarter around Mimar Sinan's mosque of 1550–1557; the Zeyrek quarter around the 12th-century Pantokrator monastery; and the 5th-century Theodosian Land Walls, which run about 5.7 kilometres across the peninsula. Together they cover the city's three imperial lives: Roman Byzantium, the Byzantine capital Constantinople, inaugurated on 11 May 330, and the Ottoman capital after 29 May 1453. Each zone had already been protected by Turkish law before 1985.
Sultanahmet Archaeological Park: the Hippodrome, Hagia Sophia and Topkapı on the First Hill
The first zone, defined in 1953 and 1956, covers the end of the peninsula at Sarayburnu, where Greek colonists from Megara founded Byzantium in the 7th century BC, traditionally in 667 BC. The acropolis of that town stood where Topkapı Palace stands now.
The oldest public space is the Hippodrome, today Sultanahmet Square. Emperor Septimius Severus built the first one in AD 203; Constantine the Great enlarged it to roughly 450 metres long and 130 metres wide, with stands for about 100,000 spectators. Its central barrier still carries the Obelisk of Theodosius, a red granite obelisk carved for Pharaoh Thutmose III around 1450 BC at Karnak and raised here by Theodosius I in 390. Its damaged shaft is 18.54 metres tall, 25.6 metres including the marble pedestal, whose reliefs show the emperor watching the races.
East of the square stands Hagia Sophia, built for Justinian I between 532 and 537 by the geometers Isidore of Miletus and Anthemius of Tralles, after the previous church burned in the Nika riots. When its first dome partly collapsed after earthquakes in 553, 557 and 558, Isidore the Younger rebuilt it higher, and the re-dedication on 24 December 562 gave the building its present form: a dome about 31 metres across, rising 55.6 metres above the floor. It was the cathedral of Constantinople until 1453, a mosque from the conquest, a museum from 1935, and has been a mosque again since 2020.
Across the square, Sultan Ahmed I built his mosque between 1609 and 1617 beside the old Hippodrome, on land cleared of several viziers' palaces; some of the Hippodrome's ancient seats turned up in its courtyard in early 20th-century excavations. Ahmed had won no major war, and the ulema protested that a sultan should fund an imperial mosque only from conquest. He built anyway, with six minarets and an interior of Iznik tiles whose blues gave the building its popular name. Our guide to the Blue Mosque covers the interior in detail.
The park also holds Hagia Irene, the first church completed in Constantinople, rebuilt by Justinian in 548 and one of only two Byzantine churches in the city never turned into a mosque, because the Ottomans used it as an arsenal. To the south, near the Marmara shore, is Little Hagia Sophia, the former Church of Saints Sergius and Bacchus, built between about 527 and 536. Under the streets 150 metres south-west of Hagia Sophia lies the Basilica Cistern, another work of Justinian's reign, where the French traveller Petrus Gyllius described being rowed between the columns in 1565. Over 50,000 tonnes of silt were removed in 1985–1987 before it opened as a museum.
Topkapı Palace fills the headland. Mehmed II ordered it in 1459, six years after the conquest, and it was the administrative centre of the Ottoman Empire from the 1460s until Dolmabahçe Palace was completed in 1853; the court moved out in 1856. The complex grew around four main courtyards, was rebuilt after an earthquake in 1509 and a fire in 1665, and became a museum by government decree on 3 April 1924. Its treasury holds the Spoonmaker's Diamond and the Topkapı Dagger.
Süleymaniye: Mimar Sinan's Mosque on the Third Hill
The second zone, protected in 1980 and 1981, centres on the Süleymaniye Mosque on the Third Hill, looking north over the Golden Horn. Suleiman the Magnificent, who ruled from 1520 to 1566, commissioned it from his imperial architect Mimar Sinan; an inscription gives the foundation as 1550 and the inauguration as 1557. It is the largest Ottoman-era mosque in the city.
Sinan deliberately echoed Hagia Sophia. The prayer hall is almost square, 58.5 by 57.5 metres, under a central dome 53 metres high and 26.5 metres across, exactly half its height, flanked by semi-domes in front and behind. Four minarets stand at the corners of a courtyard of about 47 by 57 metres; the two tallest reach 76 metres with their lead caps, and the ten balconies between them are said to mark Suleiman as the tenth Ottoman sultan. Behind the qibla wall are the octagonal tombs of Suleiman and his wife Hürrem Sultan. Suleiman's tomb bears the date 1566 and is among the earliest uses of emerald-green Iznik tiles.
The mosque was the core of a külliye with madrasas, a public kitchen and a hospital, and the protected area today holds 920 registered properties. It has survived a fire in 1660, a partial dome collapse in the 1766 earthquake and a munitions fire in the First World War; a 2007–2010 restoration removed the cement-based mortars of earlier repairs.
Zeyrek: the Pantokrator Monastery Above the Golden Horn
The third zone, protected in 1979, is the hilltop neighbourhood of Zeyrek, home to 12,863 people in 2022, with old wooden houses partly restored in the early 21st century. At its centre is the Zeyrek Mosque, the former Monastery of Christ Pantokrator and, after Hagia Sophia, the largest Byzantine religious building still standing in Istanbul.
Empress Irene of Hungary founded the monastery between 1118 and 1124, with a church, a library and a hospital. After her death shortly after 1134 her husband, John II Komnenos, added a second church to the north, dedicated to the Theotokos Eleousa, and by 1136 at the latest the two were joined by a chapel of Saint Michael that became the burial place of the Komnenos and later Palaiologos dynasties. Venetian clergy held it after the Fourth Crusade took the city in 1204, and the last Latin emperor, Baldwin, used it as a palace. One of its later monks, Gennadius Scholarius, left it to become the first Patriarch of Constantinople after 1453.
Soon after the conquest the main church became a mosque, named after Molla Zeyrek, a scholar who taught there. Unusually for Constantinople's churches, its Byzantine name was never forgotten; Pierre Gilles, the same French traveller who described the Basilica Cistern as Petrus Gyllius, wrote about it. The zone matters because it protects a whole hillside of street pattern and housing, not just a monument.
The Theodosian Land Walls: 5.7 Kilometres from the Marble Tower to Blachernae
The fourth zone, protected in 1981, is the longest: the double land walls that close the peninsula on its western side, about 2 kilometres outside Constantine's original wall. They were built under Theodosius II, directed by the praetorian prefect Anthemius, and finished in 413 according to the Codex Theodosianus, although an inscription found in 1993 suggests the work began around 404–405. When an earthquake on 6 November 447 brought down 57 towers with Attila's Huns in the Balkans, the city's chariot-racing factions rebuilt them in 60 days.
Today the walls run about 5.7 kilometres from the Marble Tower on the Sea of Marmara to the Palace of the Porphyrogenitus (Tekfur Sarayı) at Blachernae. In front of the inner wall stood an outer wall 8.5 to 9 metres high, and in front of that a moat more than 20 metres wide and up to 10 metres deep. Sixty-two of the outer wall's towers survive. The line climbs from the Golden Gate, about 14 metres above sea level, to the Gate of St Romanus near the top of the Seventh Hill at about 68 metres, dips into the Lycus valley and rises again to the Gate of Charisius, or Adrianople Gate, at about 76 metres.
These walls held off Avars and Sassanians, Arabs, Rus' and Bulgars. In 1453 Mehmed II's cannons damaged them but did not breach them, and the city fell after a siege that ended on 29 May. In 1458 Mehmed enclosed the twin towers of the old Golden Gate in the seven-towered Yedikule Fortress, built as a treasury fort and later a notorious prison for captives and enemy ambassadors.
The Ottomans kept the walls largely intact until the 19th century, when sections were pulled down as the city outgrew them. A large restoration programme has been running since the 1980s. Today the Historic Peninsula as a whole still struggles with traffic; a 2015 study found it was the part of the city that would gain most from a low-emission zone, and as of 2022 it was still described as car-oriented.
Seen from the walls looking east, the four zones read as one story: a city whose name kept changing while its hills stayed put. How Byzantium became Constantinople and then Istanbul is told in our article on where the name Istanbul comes from.