Late Roman & Byzantine Sites of Istanbul

Part Three: Aqueduct and Cisterns


26. Aqueduct of Valens

Atatürk Boulevard north of the Saraçhane Park, Fatih

The construction of a water supply system for the city of Byzantium began under Emperor Hadrian (117-138). It was expanded by Constantine the Great (306-337) and completed by Emperor Valens (364-378). That system of aqueducts and canals reached up to Thrace, being the longest in the antique world.

The water was brought to Constantinople via two lines, possibly in underground pipes, from outside lakes. The lines joined outside the walls near Edirnekapı. From there, the water was channeled along the ridges of the Sixth, Fifth, and Fourth Hills, before carried across the valley between the Fourth and Third Hills by the Aqueduct of Valens. On the Third Hill, the water was received by a large cistern, the Nymphaeum Maximum, from which it was distributed to a large area, including the district of the Great Palace.

The Aqueduct of Valens features a double tier of arches (between arches 18-73). It was originally built of limestone blocks. The stones were taken from the walls of Chalcedon (today’s Kadıköy), which had been demolished after the locals rose up against Valens in 365, in support of usurper Procopius.





The aqueduct was restored by a number of emperors until Andronikos I Komnenos (1183-1185). Later restorations in the Byzantine era altered the structure, for example, by adding bricks. It was later repaired by Sultan Mehmed II, and its course was slightly bent near the Fatih Mosque, constructed in 1463-1470. Arches 52-56 were built by Suleiman the Magnificent (1520-1566), while arches 41-45 date from the period of Sultan Mustafa II (1695-1703). The aqueduct continued to be in use until the 19th century.

Today, 921 m of the original 971 m survive. The missing 50 m section near the Fatih Mosque was pulled down in 1912.


27. Cistern of Aetius

Fevzi Paşa Caddesi, Salma Tomruk Caddesi, Kurtağa Çeşmesi Sokak & Kelebek Sokak, Karagümrük

The Cistern of Aetius was a huge open-air cistern located in what is now a stadium in the Karagümrük neighbourhood. It stood along the northern branch of the Mese and had the same water supply line as the Aqueduct of Valens. It is 244 m long, 85 m wide, and 13-15 m deep. Its walls were built using the opus vittatum technique, by alternating four courses of bricks with ten courses of stone. It is named after Aetius, who served as the praefectus urbi of Constantinople and the praetorian prefect of the East. There was a vegetable garden in the bottom of the cistern in the Ottoman era.



28. Cistern of Aspar

Next to the Yavuz Selim Mosque, Çukurbostan

The Cistern of Aspar, also known as the Great Cistern, was a major open-air water reservoir in Constantinople. It stood between the Cistern of Aetius and the Aqueduct of Valens, on the same water supply line. Tradition has it that it was also directly connected to Hagia Sophia through a canal. It was built by Aspar, an influential patrician and magister militum of Alan-Gothic origin.

The cistern is in the form of a square with sides of 152 m, and it is 10-11 m deep. Similarly to the Cistern of Aetius, its walls were built using the opus vittatum technique: five courses of bricks alternate with five courses of stone.


On the inner walls there are some remains of arches, which has led some to believe that the cistern may have been covered.

Some time later, a water tower was added near the northwestern corner of the cistern, to help regulate the water flow.



In the late-Byzantine era, the cistern was known as the Xerokepion (‘the Dry Garden’), indicating that it was out of use and empty. It was used as a vegetable garden in the Ottoman period, from which the name of the neighbourhood is derived (Çukurbostan means ‘Sunken Garden’). Until recently it was home to a little village, with houses, gardens, trees, and a mosque.


29. Cistern of Theodosius

Piyer Loti Caddesi, Dostluk Yurdu Sokak & Boyacı Ahmet Sokak, Sultanahmet

This cistern, now freshly renovated, was built by Emperor Theodosius II to store water brought via the Valens Aqueduct. 32 marble columns with Corinthian capitals and imposts support brick vaults.





30. Cistern of Philoxenos

İmran Öktem Caddesi, Sultanahmet
5th or early 6th century

This cistern is the second largest in Istanbul, after the Basilica Cistern. In Turkish it is known as Binbirdirek Sarnıcı, which means the ‘Cistern of 1,001 Columns’. In reality, it is made up of 224 columns. The columns are each 12-15 m high and made of Proconnesian marble. Each column is actually formed by placing one shorter column on top of another and fixing them with a stone collar. Now only the upper column and a short part of the lower column can be seen. The original height of the cistern can be seen in the middle of the cistern, in an excavated pond with four columns. On most of the columns, a mason’s mark can be found. The vaults that the columns support consist of bricks arranged in concentric squares.

The Philoxenos after whom the cistern is named was either a contemporary of Constantine the Great, a magister officiorum during the reign of Theodosius II, or Flavius Theodorus Philoxenus, one of the consuls of the year 525. The attribution of this cistern to Philoxenos is, however, sometimes doubted.





31. Basilica Cistern

Yerebatan Caddesi 1/3, Sultanahmet

This cistern, known in Turkish as Yerebatan Sarnıcı, or the Submerged Cistern, was built in 532 by Justinian I. The ‘basilica’ in its name refers to its presumed location underneath a 3rd- or 4th-century basilica, reconstructed by general Flavius Illus after a fire in 476.

The function of the cistern was to supply the Great Palace with water. Water was brought here via series of aqueducts from what is known today as the Belgrade Forest. It is the largest of the several hundred ancient cisterns that lie beneath Istanbul. In the Ottoman era, it provided water for the irrigation of the gardens of the Topkapı Palace.

The cistern is a forest of marble columns of 9 m. The columns are topped with mostly Corinthian and Ionic, but also some Doric capitals. They support groin vaults.

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One column, known as the hen’s eye column, is engraved with stylized motifs of eyes, tears, or lopped branches. This style makes one think of the columns of the triumphal arch in the Forum of Theodosius. Some texts suggests that the tears pay tribute to the hundreds of slaves that died during the construction of the cistern.

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At the far end of the cistern, two bas-reliefs in the shape of Medusa’s head have been placed under two columns. Like the majority of the columns in the cistern, they appear to have been brought from the ruins of older buildings from other parts of the empire, possibly together with the construction elements of Hagia Sophia, which was being built at the same time. As the Medusa’s heads were seen as building rubble, one of them is upside down, while another one is on its side. Tradition has it that they were placed in this way in order to negate the power of their gaze.

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