Pretty old.
"The current building was originally constructed as a church between A.D. 532 and 537 on the orders of the Byzantine Emperor Justinian, and was in fact the third Church of the Holy Wisdom to occupy the site (the previous two had both been destroyed by riots). . . The first church of Hagia Sophia was inaugurated by Constantius II on 15 February 360."
Missed 76, didja? ;)
It’s now a mosque.