After the Ottomans conquered Constantinople and transformed Hagia Sophia into an Imperial Mosque, the decorations inside Hagia Sophia changed to calligraphic representations of god’s name, rather than literal depictions of the human figure. In the Islamic tradition, only Allah has the power to create life, and so they did not create artistic depictions of the human form. In the Images below, calligraphy can be seen used as grand decorations in the interior of Hagia Sophia.
Interior of Hagia Sophia
Calligraphy rounds in Hagia Sophia