This city founded around a subterranean cavern qualified plutonian which was a religious centre developed, beginning from the hellenistic age and became an important place.
When Attalos, king of Pergamum, yielded his territory to Rome in 133 BC the city was subordinated to the Asian province. According to Plinus it must have been incorporated into the region under the domination of Cibyra. The city was destroyed by earthquakes which occurred during the reigns of Tiberius in 17 AD and Neron in 69 AD Hierapolis which led a peaceful life in IInd century lived an economic prosperity. The emperor Hadrian affranchised the city from aurum coronarium and recognized the right to take refuge in there. The city lived through hard times during the second half of the IInd century because of the plaque. It was restored under Antoninus and Severius. The importance of the city increased because of the Temple erected to the name of Saint Philippe who was crucified here in 80 AD and the city became the seat of a metropolis. The city continued to flourish during the Byzantine Period. Constantin the Great made the capital of Phrygia. However its decline started as of XIIth century.
Hierapolis became the site of excavations for the first time in 1887 under the administration of C. Humann and then in 1957 by an Italian committee headed by Prof. Paolo Verzone. The excavations are still continuing. The artifacts found are exhibited in the two halls of a Roman pool used now as a museum. The statues made under the influence of the School of Sculpture of Aphrodisias are exhibited. The city built on a platform at an altitude of 376 m. from the sea level was conceived within the scope of a Hippodamos plan which was very popular at the Hellenistic period of which illustrative examples may be seen at Priene and Miletos. This platform resting on blocks of limestone rocks measuring 1000 x 800 m and which rises to 70 m from the plain presents an exquisite beauty .The city is rectangular and is divided by identical streets into blocks of houses which are themselves rectangular in shape. Each street comprises to houses measuring 29.60 by 70 m. The streets must have been reserved for pedestrians as no trace of any cart weels has been encountered.
All the streets directed from north towards the south crossed the city and the most important among them was Plateia of a length of 13 m. It was probably lined with a colonnade. The city destroyed by an earthquake in 60 AD under Neron was rebuilt in a way and the Temple of Apollo and the Theatre in the centre of the city was entirely restored. They added two new quarters to the north and the south of the city; these joined with the axis of Plateia established the communication by means of two portals. We know that the soffit of the north gate was flanked by two towers. These soffits were surmounted by an architectural element with columns of which nothing remains today. The inscription on the frieze in two languages says that it was done by Julius Sextus Frontinus, proconsul of Asia and consecrated to Domitianus.
The facdes at the ground level of these new dwellings were doric and were decorated by columns of which the upper storeys had window apertures. This restored quarters had a sewage system.
Following the economic development of the city in IInd and IIIrd centuries the theatre, the baths and the nymphaeum and towards the end of IIIrd century the walls of Hierapolis were constructed. The walls encircled the same space which was surrounded during the Hellenistic Period. The houses along this perimeter were pulled down, the debris of which served in the construction of the walls with 28 square towers, two portals and two underground passages.
The gates which opened on to the plateia the southern one and especially the northern one are still visible today. One of these passages links the city and the martyrium on the summit dating from the same years.
The other passage links the city the cemetery of the east as well as the aquaducts and the cistern.