Basilica Cistern

Under the city

The largest of several hundred ancient cisterns beneath Istanbul

The Basilica Cistern is the largest of several hundred ancient cisterns beneath Istanbul. It was built in the 6th century during the reign of the Byzantine emperor Justinian I, southwest of the Hagia Sophia. Today it is kept with little water for public access.

150 metressouthwest of the Hagia Sophia

The name

It is named for a great basilica that stood on the spot

Before the cistern, a great basilica stood on the spot. It had been built in the Early Roman Age between the 3rd and 4th centuries as a commercial, legal and artistic centre. The cistern took its name from the large public square above it, the Stoa Basilica.

Forgotten

It was forgotten by all but the locals who drew water from it

The existence of the cistern was eventually forgotten by all but the locals who still drew water from it. In 1565 the French traveller Petrus Gyllius left a record of it. He wrote of being rowed in between the columns and seeing fish swimming in the water beneath the boat.

The columns

A forest of 336 marble columns holds up the ceiling

The chamber is about 138 metres by 65 metres and can hold 80,000 cubic metres of water. A forest of 336 marble columns, each 9 metres high, supports the ceiling. The majority appear to have been recycled from the ruins of older buildings, a process called spoliation.

336marble columns, in 12 rows of 28

Medusa

Two column bases reuse blocks carved with the face of Medusa

The bases of two columns in the northwest corner reuse blocks carved with the face of Medusa. Their origin is unknown. In the restoration between 1985 and 1987, more than 50,000 tons of silt were removed, uncovering them. The cistern opened to the public as a museum in 1987.