The mythological king Midas (738-696 BC) is said to have ruled a larger Phrygian empire from Pessinus. Archaeological investigations carried out since 1967 have shown that the city developed at the earliest around 400 B.C., which contradicts any historical assertion of earlier Phrygian roots.

According to old tradition Pessinus was the most important cult centre of the Kybele cult. The Greek-Phrygian Kybele is rooted in the ancient Anatolian goddess Kubaba, whose cult spread over Anatolia in the second millennium BC. The tradition transports the cult of Kybele to the early Phrygian period (8th century BC) and combines the construction of its first significant temple and even the foundation of the city with King Midas (738-696 BC). However, the Phrygian past of Pessinus is still unclear and controversial both historically and archaeologically.

The temple for the imperial cult (Augustus) was enthroned above the Agora in the centre of the city. It was part of a Sebasteion referring to the imperial cult. The temple was accessible via a central staircase with two cavea wings that could be used as a theatre.
The temple area, which was excavated between 1967 and 1972, is the only well researched area of the Pessinus. It was thoroughly investigated by M. Waelkens (current director of the Sagalassos excavations) in the 1980s and between 2006 and 2012 by Angelo Verlinde (University of Ghent).

It was finally determined that the excavated temple could not be identified as the Temple of Kybele, as researcher Charles Texier assumed when he "discovered" the temple's foundations in 1834. The decorative elements were designed in a conservative Augustan manner, suggesting that the building was probably built in the late Augustan period (about 15 AD).

The geographer Strabo, for example, writes that the priests were potentates in "old times". But it is not clear whether Pessinus was already a temple state which was ruled by a dynasty of priests in the Phrygian period.

According to Cicero, the Seleucid kings held a deep devotion to the shrine of Kybele, suggesting that the sanctuary was still highly venerated at that time.
By the 3rd century BC at the latest, Pessinus had become a temple state ruled by a clerical oligarchy consisting of Galloi, eunuch priest of the mother goddess.

After the arrival of the Celtic tribes in Asia Minor in 278/277 B.C. and their defeat during the so-called "Battle of the Elephants" (probably 268 B.C.) by Antiochus I, the Celts settled in northern Anatolia, known as Galatia.
The Tolistobogi tribe, a Celtic tribe, occupied the Phrygian territory between Gordium and Pessinus.

The Roman commitment to the Pessinus has early roots. Unsettled by several meteor showers during the Second Punic War, the Romans decided in 205/204 B.C., after consulting the Sibylline books, to introduce the cult of Kybele in Rome. They sought help from their ally Attalus I (241-197 B.C.). According to his instructions they occupied Pessinus at short notice and removed the most important cult object of the goddess, a large black stone which should have fallen from heaven, and brought it to Rome (Livius 10,4-11,18). Pergamum seems to have gained some control over Pessinus towards the end of the 3rd century BC. With Pessinus a sanctuary was left behind after 183 BC by the Attalid kings.

The first century BC was a very unstable time for Pessinus, during which many rulers ruled over Central Anatolia. After Strabo (12.5.3) the priests gradually lost their privileges. The Mithrid wars (89-85 B.C.; 83-81 B.C.; 73-63 B.C.) caused political and economic turbulence throughout the region. When Deiotaros , Tetrarch of Tolistobogi and faithful vassal of Rome, became king of Galatia in 67/66 B.C. or 63 B.C., Pessinus lost his status as an independent, holy principality. In 36 B.C., Marcus Antonius transferred the dominion over Galatia to King Amyntas. After the death of the monarch, the empire of the Galatians was annexed by Emperor Augustus Roman Empire as the province of Galatia. Pessinus became the administrative capital of the Galatian tribe of the Tolistobogi and soon developed into a true Greek-Roman polis with a variety of monumental buildings such as a colonnade road and a temple for the imperial cult.

Central staircase with two Cavea wings below the temple of Augustus

Strabon called Pessinus an 'Emporion', a commercial centre. It can be assumed that products from the Anatolian highlands, especially grain and wool, were traded. Very soon after 25 B.C., the temple state was urbanised and transformed into a Greek polis.

Constructions such as a Corinthian temple and a colonnade road (cardo maximus) were built with marble from the quarries in Istiklalbagi, 6 km north of the city.

The Agora

The Agora in the valley was reconstructed by the Belgian archaeologist Angelo Verlinde. In the past this structure was wrongly dated to the Tiberian period. Verlinde, however, was able to prove that the square had already been built in Hellenistic times (late 2nd to early 1st century BC).

Among the other monumental buildings erected during the reign of Tiberius were the Emperor's Cult Temple, a Sebasteion, accessible via a central staircase with two cavea wings that could be used as a theatre where religious and other performances such as gladiator fights took place.

Inscriptions show that Pessinus owned several public buildings, including a gymnasium, a theatre, an archive and baths. A water supply system was set up through channels and terracotta pipes. The most impressive public building of the early imperial period was the sewerage system, the earliest part of which dates from Augustus. It channelled the city's sewage into the river Gallos, which crossed the city. From the 1st to the 3rd century A.D. the sewerage system was continuously extended until it finally had a length of about 500 m and a width of 11 to 13 m. The sewerage system was built in the middle of the city.

When exactly the great theatre was built is not known. It is unexcavated. Today only the hollow of the cavea can be seen. It has been handed down that the theatre was last lavishly restored under Hadrian.

Christianity reached the area in the 3rd century. At the end of the 4th century the temple of Augustus was abandoned. At the end of the year 715 the city of Pessinus together with the neighbouring city of Orkistos was destroyed by an Arab invasion. The area remained under Byzantine control until it fell under Seljuk rule in the late 11th century. Then Pessinus became an inconspicuous mountain village, which was gradually depopulated.