The archaeological excavation in the Iranian historical city of Sad-Darvazeh (Hektumpolis), Iranin major capital city at the time of Arsaces/Parthian dynasty, would erase much of current ambiguity about the history of Damghan and its neighboring areas.

Sad-Darvazeh was one of the most thriving cities of the Arsaces dynasty, which has raised a lot of doubts about the era (c. 247-211 B.C). “The exact location of the city is contentiously disputed. Some believe it is located near the village of Ghoshe, whose developments had gradually wiped off the ancient city. The presence of some caravansaries and aqueducts support the theory,’ said Majid husseini, head of Damghan’s Cultural Heritage and Tourism Organization. “Others believe that the city of Sad-Darvazeh is located near today’s Damghan, while others maintain Damghan was built on its ruins.”

Arsaces I was the first king of the Parthians. Arrian reported Arsaces I was descended from Arsaces, son of Phriapites, and that his brother was Tiridates. Confusion exists among historians as to whether Arsaces I or his brother Tiridates ruled until 211 B.C., but it is generally accepted today that Arsaces I was the king and Arian's references to Tiridates should be attributed to Arsaces.

Arsaces I overthrew Andragoras, the Seleucid governor of Parthia and was crowned in 247 B.C. in Asaak (Arshaak), the capital city of Astauene. Arsaces I had to deal with attempts by Antiochus III to recapture lost Seleucid territories, but evidently succeeded in consolidating control of Parthia, Hyrcania, Herat and Astauene (and possibly Nisaia). Early in his reign of 36 years he liberated Hyrcania and then, on the death of the elder King Diodotus in Bactria, formed and alliance with Diodotus II. About 228 B.C., Seleucus II Calinicus (247-226 B.C.) gathered an army in Babylon with which he marched east to reclaim the lost satrapies.

Arsaces I retreated before him and eventually sought refuge among the Iranian Sakae, but circa 227 B.C. he returned victorious to Parthia when other troubles in Syria diverted Seleucus II. Following his death, Seleucus II was succeeded by his elder son Seleucus III Soter who ruled only three years until his murder, to be succeeded in turn by his younger brother Antiochus III (the Great) in 223 B.C. While Antiochus III was concerned with rebellion by two of his generals, the brothers Molon and Alexander, Arsaces continued to consolidate his position, increase his army, build forts and establish new cities such as Apaortenon, an almost impregnable position.