One of the magnificent historical constructions of Istanbul is the Basilica Cistern, located near south-west of Ayasofya (Hagia Sophia). This huge cistern, which was founded by Justinianus I, a Byzantine Empire (527-565), began to be called by the public 'the Sinking Palace' - and not without a reason, seeing the great number of marble columns arising out of the water. In place of the cistern was formerly found a great Basilica, which had probably been built in IIIrd or IVth century during the Early Roman Age to be used in commercial and legal affairs and scientific and artistic activities