In the early part of the 1st millennium B.C. and the 1st millennium AD there were 18 km west from Ashgabat, overlooking the remains of Nisa, capital of ancient Parthia. The capital of Parthia in the third century BC was Modern Nisa, and then the royal residence was an Old Nisa Castle.
Old Nisa was the center of the concentration of palace and temple buildings. A treasury, broad wine shop and storerooms were also situated with several inventories. The foundation of the fortification walls was 8-9 m thick and consolidated with 43 rectangular towers.
Old Nisa was renamed Mitridatkert, after the name of King Mitridate (171-138 BC), who directed the building of this City during the time of the Parthians Empire. Later on this capital was moved to Asia Minor, but a special mentality was maintained toward Old Nisa: there were tombs of the ruling dynasty Arsacid dynasty rulers.
In the following year the Parthian Reign came to an end, with the new Sassanid State founded by Artashir, the former governor of Arsacid. In order to expand anything relevant to the Parthian rulers from the memories of the citizens, he ordered Old Nisa to be killed. The land of Arsacid was plundered and virtually destroyed. Just a few years later, after Nisa became part of the Arab Caliphate, life was restored, but this fortress never acquired its past power. The archeological discoveries – exquisite ivory-horn pots (rhythons), special records of the II-I centuries BC, now reveal the ex-majesty of Mitridatokert.
A rare fragment of fresco is a true masterpiece of Parthian pictorial architecture, as a latest discovery in Old Nisa.
UNESCO declared the Nisa fortress a UNESCO World Historic Site in 2007.