Which emperor built the landmark church of haigia sophia in constantinople

Justinian I, Emperor of the Byzantine Empire, ordered the landmark church of Hagia Sophia in Constantinople. It was built by Greek scientists Isidore of Miletus and Anthemius of Tralles. Hagia Sophia was an Orthodox Christian Church, then became a Roman Catholic Church and then became a mosque, before it became secularized and became a museum, which is open today and attracts many tourists.