Nisa, an ancient and medieval city located in the foothills of the Kopet Dag, near the modern village of Bagir (18 km from Ashgabat), now consists of the ruins of two citadels: New Nisa and Old Nisa. The earliest traces of human activity in the area of Nisa date back to the 4th-2nd millennium BCE. By the 1st millennium BCE, there was already a significant settled settlement.

In the 4th century BCE, the region of Parthia (with its capital in Nisa) became part of the state of Alexander the Great, who established the city of Alexandropolis near the fortress of Nisa. After Alexander's death, Parthia briefly fell under the rule of the Hellenistic Seleucid Empire. In 250 BCE, the governor of Parthia, Andragoras, declared independence from the central authority. In 245 BCE, local semi-nomadic tribes known as the Dahae-Parni, inhabiting the Caspian steppe, rose in rebellion under the leadership of two brothers, Arsaces and Tiridates. They seized power in Parthia, making Nisa their capital, thus laying the foundation for the great Parthian Empire.

On the site of the settlement, the ancient city of New Nisa (covering an area of about 18 hectares) grew, with residences of the slave-owning aristocracy and a temple. During the reign of Mithridates I (174-136 BCE), the royal fortress of Mithradatkert (covering an area of about 14 hectares) was erected on the site of Old Nisa, with 43 towers. Although the capital of the Parthian Empire was later moved to Anatolia during its heyday, the rulers maintained a special connection to Nisa. The tombs of the Arsacid dynasty members were located here.

It was during the period of Parthian cultural flourishing in the 3rd-1st centuries BCE that numerous archaeological discoveries were made in the mid-20th century. These include the ruins of palace-temple architecture with monumental clay sculptures, marble statues, a whole collection of cult rhytons made of ivory with relief ornamentation, decorations, small metal and terracotta figurines, weaponry, household items, and more. Also found were economic documents (mostly related to wine production) written in the Aramaic alphabet in the Parthian language.

In 226 CE, the Parthian Kingdom ceased to exist. Ardashir, the governor of the Arsacid dynasty in Persis, established a new state under the rule of the Sasanian dynasty. The first to be destroyed was Old Nisa, as it held the dynastic legacy of the Parthian kings. Life there resumed only several centuries later.

The South Turkmenistan Archaeological Complex Expedition (STACE), led by Academician M.E. Masson, made the most significant contribution to the scientific study of Nisa throughout its existence. Masson began working in Nisa in the 1930s. The discovery of the treasure trove of Parthian kings by the expedition caused a sensation, and most of the items are now part of the collection of the National Museum of Turkmenistan.