The Basilica Cistern is the largest of several hundred ancient cisterns that lie beneath the city of Istanbul, Turkey. The cistern, located 150 metres southwest of the Hagia Sophia on the historical peninsula of Sarayburnu, was built in the 6th century during the reign of Byzantine emperor Justinian I. Today it is kept with little water, for public access inside the space.
This subterranean cistern was called Basilica because it was located under a large public square, the Stoa Basilica, on the First Hill of Constantinople. Prior to its construction, a great basilica stood on the spot. It had been built during the Early Roman Age between the 3rd and 4th centuries as a commercial, legal and artistic centre. The basilica was reconstructed by Illus after a fire in 476.
Ancient texts indicated that the basilica cistern contained gardens surrounded by a colonnade that faced the Hagia Sophia. According to ancient historians, Emperor Constantine built a structure that was later reconstructed and enlarged by Emperor Justinian after the Nika riots of 532, which devastated the city.
Historical texts claim that 7,000 slaves were involved in the construction of the cistern.
The enlarged cistern provided a water filtration system for the Great Palace of Constantinople and other buildings on the First Hill, and continued to provide water to the Topkapı Palace after the Ottoman conquest in 1453 and into modern times.
The existence of the cistern was eventually forgotten by all but the locals who still drew water from it until, in 1565, the French traveller Petrus Gyllius left a record of it. Gyllius recorded being rowed in between the columns and seeing fish swimming in the water beneath the boat.
The Basilica Cistern has been restored several times since its original creation. During the 1985 restoration, 50,000 tons of mud were removed from the cistern, and platforms were erected to replace the boats previously used for touring the cistern. The cistern was opened to the public in 1987.
This cathedral-size cistern is an underground chamber approximately 138 metres by 65 metres, capable of holding 80,000 cubic metres of water. The ceiling is supported by a forest of 336 marble columns, each 9 metres high. The capitals of the columns are mainly in the Ionic and Corinthian style, with the exception of a few Doric capitals with no engravings. One of the columns is carved with raised pictures of a Hen's Eye, slanted branches, and tears, and resembles the columns of the 4th-century Triumphal Arch of Theodosius I (AD 379–395), erected in the 'Forum Tauri' Square, today's Beyazıt Square. The majority of the columns in the cistern appear to have been recycled from the ruins of older buildings. They are carved out of different types of marble and granite.
The bases of two columns In the northwest corner of the cistern reuse blocks carved with the face of Medusa. The origin of the two heads is unknown, though it is thought that they were brought to the cistern after being removed from a building of the late Roman period. There is no evidence to suggest that they were previously used as column bases. Tradition has it that the blocks are oriented sideways and inverted in order to negate the power of the Gorgons' gaze.
References:The Walls of Constantinople are a series of defensive stone walls that have surrounded and protected the city of Constantinople (today Istanbul) since its founding as the new capital of the Roman Empire by Constantine the Great. With numerous additions and modifications during their history, they were the last great fortification system of antiquity, and one of the most complex and elaborate systems ever built. They were also the largest and strongest fortification in both the ancient and medieval world.
Initially built by Constantine the Great, the walls surrounded the new city on all sides, protecting it against attack from both sea and land. As the city grew, the famous double line of the Theodosian Walls was built in the 5th century. Although the other sections of the walls were less elaborate, they were, when well-manned, almost impregnable for any medieval besieger.