Dedicated to the "Divine Wisdom" (Hagia Sophia), this great structure was built between 532-537 A.D. at the orders of the emperor Justinian. Its architects were Anthemius and Isidoros. A smaller church originally built here in 360 was destroyed in a fire in 404. Rebuilt eleven years later, the church was again destroyed by fire in 532 during a popular uprising.

The interior of Ayasofya was richly decorated with mosaics, many of which are still in palace. Over the door leading into the inner narthex is a famous mosaic depicting Mary holding the infant Christ her lap. To her right stands Constantine presenting a model of his new city while to her left is Justinian holding a model of his new church. The mosaic is in fact from the 10th century.