The first archaeological studies began by a German Excavation Group in 1887 under the direction of Prof. Carl Human. Then, in 1957 the Italian Excavation Group directed by Prof. Verzone handled the excavations.
By the same team, restoration works had been held since 1973.
Because of the earthquakes in the past, most of the ruins that are standing in Hierapolis today date only from the Roman and Early Christian periods. The city was rebuilt couple of times on Roman time after the earthquakes.