This subterranean cistern was called Basilica because it was located under a large public square, the Stoa Basilica, on the First Hill of Constantinople.[2] 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.[1] 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.[1] 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.[1]
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.[3]
