In 1453 Constantinople was conquered by the Islamic Ottoman Turks, and this ended the Byzantine Empire. Already weak because the Black Plague killed almost half of Constantinople’s citizens between 1346 and 1349, and because the city and its empire never really recovered from the sacking in 1204, the city was utterly defeated.
It is said that Sultan Mehmed II rode his horse up the steps and entered the Hagia Sophia on Tuesday and ordered the cathedral to be changed over to a mosque, and on Friday, they opened the doors to Friday Mosque. The church became a mosque but was left intact. The bells, sacrificial vessels and icons were removed, frescoes and mosaics plastered over, and the mosaics painted yellow.
The new mosque added four minarets outside that were each 200 feet tall. They left the mosaic of the Virgin Mary (Theotokos) and baby Jesus in the apse, and added four monograms of the four caliphs on the pillars in front of the apse and the entrance to the nave. They changed the name of the sacred building from the Hagia Sophia to the Aya Sofya.It would later inspire the design of the Blue Mosque.
The mihrab, seen above, points the direction to Mecca. Notice the caligraphy adorning it, in the green plaques, and on the sides. It was said that Muhammad said, “God is beautiful – God loves beauty.” This mihrab is a wonderful example of how no space is left unadorned by beauty.