The Basilica Cistern (Yerebatan Sarayi)
is located near Haghia Sophia, at the beginning of the Yerebatan Avenue.
Byzantium
was first supplied with water coming from Thrace by means of a system of aqueducts such as the Aqueduct of Valens built in 375 and which still can be seen between the districts of Fatih and Süleymaniye. When this water became unusable due to the barbarian hordes (including the Avars, the Huns and the Bulgars) that threatened Byzantium and actually came to the very foot of the city walls, a large number of cisterns of different sizes in which rain water could be collected were built. Most of the Byzantine cisterns were not used any longer by the Ottomans who prefered running water.
The largest and the most beautiful in architecture is the Basilica Cistern built during the reign of Justinian. It is surrounded by a 4m / 13 ft thick wall made of brick covered with a waterproof mortar. This huge underground cistern, which covers an area of 9,800 square meters, is 140m / 460 ft in length and 70m / 230ft in width. The vaults, made of brick, are supported by 336 marble columns which are 9 m / 29.5 ft high and arranged in 12 rows. Each row consists of 28 columns placed at an interval of 4.90 m/ 16 ft. Most of the columns are topped with Corinthian style capitals, and some others with Doric style capitals. At the far end of the cistern (northwest corner), two beautiful sculptures representing the head of Medusa and coming from Roman antique temples, are used as bases to the columns. Medusa, a mortal whose hair had been turned into snakes by Goddess Athena who was jealous of her love for Perseus, had the power of transforming those who looked at her into stone by a mere glance. She was one of the three Gorgona sisters.

Soft classical music and lighting effects increase the strangeness of the place that the Ottomans named the "underground palace". Not very far, there is a dried underground cistern called "1001 Columns Cistern" (Binbirdirek Sarnici).
(open 09.00 - 17.00.)
Map 2, E 3


Column scupted as trunk of tree


One of the heads of Medusa is tilted to on
They seem to have been placed

e side while the other head is upside down.
deliberately in that way.
 
Haghia Irene, which is located in the first courtyard of Topkapı Palace, was one of the very first Christian sancturaries in the city and was erected on the site of a previous pagan temple. The church was later enlarged by Emperor Constantine. Like former Haghia sophia which was connected to it, and as the result of the Nika Revolt (nika was the people's cry which meant "win" during the games) against Justinian in 532, the church was destroyed by a fire and rebuilt later. Haghia Irene, which is a beautiful example of Byzantine architecture with its original atrium, did not undergo many changes as it was not turned into a mosque after the conquest of Constantinople.
The monument was used as a spoils and weapon warehouse for a long time and became Empire Museum in 1869 and Military Museum in 1908, until it was emptied in 1946 and restored. Today it is used for concerts of classical and sacred music.
Map 2, E 3


 

SOME BYZANTINE CHURCHES CONVERTED INTO A MOSQUE
 
Küçük Ayasofya camii (Little Aghia Sophia) : ancient St Serge and Bacchus Church is located at the end of Küçük Ayasofya Road near the Coastal Road. The architectural art corresponding to the reign of Justinian started with St Serge and Bacchus Church (built on an octogonal plan between 527 and 536) which is considered to have been the first step towards Haghia Sophia.
Map 2, F 3

Mollazeyrek camii
, located half way between the Aqueduct of Valens and the Golden Horn, was formerly called the Monastery of the Pantocrator. The monastic complex, one of the largest Byzantine monasteries, was founded by Emperor John II Comnenus (1118-1143) and his wife Irene. Originally it comprised two churches, the Church of Christ Pantocrator (the Almighty) and the Church of Panagia Eleousa (the Merciful), and between was the funerary Chapel of St Michael where John, Irene and other members of the Comnenian family, were buried.

Their son, Manuel I Comnenus (1143-1180) brought from Ephesus the marble slab believed to have been the Stone of Unction, on which Christ's body had been laid out before the entombment. When the Crusaders seized Constantinople in 1204, the monastery was taken over by the Venitians who sent the sacred relics, the valuable historic icons and manuscripts, gold and silver vessels to the Church of St Marco in Venice. During the Palaeologan period, the monastery of the Pantocrator became the centre of opposition to the movement of union of the Greek to the Roman Catholic Church.
The churches and chapel, which are joined by a common narthex and exonarthex, had a lavish wall and floor decoration including coloured marble coverings and mosaics. The mosque is located in the larger and taller Church of Panagia Eleousa.
From the nice terrace gardens in front, there is a panoramic view over the Goldern Horn, the Süleymaniye Mosque and the Beyazıt Tower.
Map 2, D 1/2
 
Eski Imaret Camii, formely called the Church of Saint Saviour Pantepopte (All-seeing Saviour), is located in the area of Zeyrek. It was built in the late 11th century by Anna Delasenna, Emperor Alexius Comnenus I's mother, who retired in the monastery where she died in 1105. When the Crusaders took Constantinople in 1204, the church was consecrated to the Latin cult and most of the relics where taken to Venice and to other Western countries. Three of the five naves which composed the church have remained and are preceded by a narthex and an exonarthex.
 
Fethiye camii, formerly called the Theotokos Pammacaristos Church (Blissful Virgin Church), is located at Fener. A church formed by a main sanctuary was built in the 11 th century by John Comnenus and his wife Anna Doukaina. The church was rebuilt in the early 14 th century by Michael Glabas who added a side chapel to the southeast as a burial place for himself and his family. The finest examples of golden mosaics dating from the 14 th century can be seen here. In 1455, the Orthodox patriarchate was transferred here from the Church of the Saint Apostles, then moved to St George Church in 1586 when the church was turned into a mosque.

Its Turkish name, meaning “Mosque of the victory”, was given to commemorate Sultan Murat III 's victories. While the main building is still used as a mosque, the funerary chapel which contains the mosaics is now a museum currently open to visitors.
Map 2, C 1
 
Fenari lsa Camii formely was the Monastery of Constantine Lips, a monastic complex composed of the Church of the Theotokos Panachrantos (the Immaculate Mother of God) built in 908 by Constantine Lips, a high official in the service of Leo Vl the Wise (886-912) and later of Constantine VII Porphyrogenitus. South of this church, the Church of St. John the Baptist also called St. John the Prodrome , and a small funerary chapel which were added in the late 13th century by Theodora, spouse of Michael Vlll Palaeologus (1261-1282). This imperial convent for ladies sheltered numerous tombs, including those of the Empress Theodora herself and of her daughter Eudocia. The churches were turned into a mosque in the late 15 th century. After the fire in 1622 which severely damaged the complex, the columns were removed and replaced by large pointed arches, and the roof and the two domes were reconstructed. The buildings were damaged again by the fire in 1917 and remained for many years in a neglected state.

The restoration work has highlighted the elaborate brick and ashlar decoration in the east side of the churhes, the fragments of mosaics and the inscription on a golden background related to Theodora, in the Church of St. John the Prodrome. Fenari lsa Camii is located in Fatih on the Adnan Menderes Bulvarı.
Map 4, E 3


11C Inlaid Marble Icon of St Eudocia
from Monastery of Constantine Lips
Istanbul Archaeological Museum
 
Gül camii is located in the Cibali area near the Golden Horn. Old St Theodosia Church was built in the late eleventh or early twelfth century to honour the memory of Virgin Martyr Theodosia. It is said that when the city was captured on May 29, feast of the Saint, the church was decked by roses, hence its Turkish name Gül Camii meaning "Mosque of the Roses". Another theory is that its turkish name comes from the dervish called Gül Baba burried here.
Map 2, C 2

 
Vefa Kilise Camii formely was called St Theodoroi Church. The exact date of construction is uncertain. According to different sources it was built either in the late 11th or early in the 13th century. The church was converted into a mosque by theologian Molla Gürani some time after the conquest of Constantinople. This small but charming edifice is a beautiful example of Byzantine religious architecture and still bears traces of mosaics, frescoes and sculptures inside. Like Kalenderhane Camii, this mosque is located in the area of Süleymaniye Mosque.
Map 2, D 2
 
Kalenderhane camii formely was the Church of Theotokos Kyriostissa built approximately in the late 12th century. The church is believed to have been part of the earlier Monastery of Christ Akataleptos built long before under the reign of Justinian. When the Crusaders took Constantinople in 1204, the church was consecrated, during some fifty five years, to the Latin cult. A fresco depicting the life of Saint Francisco of Assisi was discovered in one of the side chapels. Beautifully restored, it is now displaid in the Archeological Museum. Some fragments of sculptures, mosaics and paintings can still be seen in the western part of Kalenderhane Camii. Like Vefa Kilise Camii, this mosque is located in the area of Süleymaniye Mosque.
Map 2, D 2
 
Bodrum camii: the Church of the Myrelaion Monastery was built in the early 10 th century by Romanus I Lecapenus. Below the edifice is a crypt, almost repeating the cross-in-square plan, which has given the name of Bodrum (basement) Mosque. Outside is the entrance to the remarkable circular cistern or Rotonda (cannot be visited). Seventy of the columns have survived. Several members of the Macedonian and Comnenus dynasties were buried in the monastery which was destroyed by fire first in 1784, and in 1911 by the great fire which ravaged the Grand Bazaar and Laleli area. The church and cistern have been restored in the 1990's.
Map 2, E 1
 
The Valens Aqueduct's (Bozdoğan Kemeri) construction was started by Emperor Constantine but was only achieved by Valens in 378. It was used to provide the Byzantine cisterns and palaces (and later Topkapı Palace) with water coming from the surrounding hills. Its initial length was about 1 km / 0.62 miles and it stretched from Fatih Mosque to the actual Beyazıt University. The aqueduct was damaged and restored many times.
Map 2, D 1