This church, built by the Byzantine Emperer Theodosuis II, is situated outside the city walls 'in istanbul city'.
In 1511, the mosaics were covered with plaster, a minaret was added, and it was converted into a mosque. It was repaired during the period of the Republic, and was later converted into a museum after the mosaics were cleaned and restored. With an inner and an outer narthex to the west, a burial chapel to the south, and a gallery to the north, the building covers an area of 20 m x 28.5 m. The floor of the main building and the narthex walls, are decorated with white and colour-streaked marble. It is especially famous for its extremel beautiful mosaics which were made during the period of the Palaeogolos in the first quarter of the 14th century.
The mosaics 'chora mosaics' on the ceiling and walls of the outer entrance depict the birth and miracles of Jesus, while the Virgin Mary is pictured on the inner aisles. The mosaics on the right of the altar show Jesus in Mary's lap and on the left, Jesus holding a Bible; above the entrance door to the hall one can see the burial ceremony of the Virgin Mary. The inner and outer mosaics, having been made in different time periods, are in different styles.