[Picture: Coin of Arsaces I. The reverse shows a seated archer carrying a bow]
Parthia’s rulers, the Arsacid dynasty, belonged to an Iranian tribe that had settled there during the time of Alexander. They declared their independence from the Seleucids in 238 BC.
During the Parthian period, Hellenistic customs partially gave way to resurgence of Persian culture. However, the empire lacked political unity. The administration was shared between Seven Parthian clans who constituted the Dahae Confederation, each of these clans governed a province of the empire. Suren-Pahlav Clan, Karen-Pahlav Clan and Mihran Clan were the most influential ones. By the 1st century BC, Parthia was decentralized, ruled by feudal nobles. Wars with Rome to the west and the Kushan Empire to the northeast drained the country's resources.
Parthia, now impoverished and without any hope to recover the lost territories, was demoralized. The kings had to give more concessions to the nobility, and the vassal kings sometimes refused to obey. Parthia's last ruler Artabanus IV had an initial success in putting together the crumbling state. However, the fate of the Arsacid Dynasty was doomed when in AD 224, the Persian vassal king Ardashir revolted. Two years later, he took Ctesiphon, and this time, it meant the end of Parthia.