Arsacid Dynasty: Encyclopedia II - Arsacid Dynasty

In 247 BC two brothers, Arsaces (Arschag) and Tiridates, members of the nomad iranic tribe of the Parni, first mentioned in this century and migrating south from the banks of the Amu-Darya, occupied the Seleucid satrapy of Parthia (the district of Tejen) by defeating and killing its governor Andragoras. They were years of great tumult and difficulties for the House of Seleucus, which had also a few years before lost control of Bactria with the rebellion of the Greek satrap Diodotus.

The Parthians remained on the defensive for nearly a century; a century in which the world scenery was radically transformed. In particular, in 190 BC the Seleucid king Antiochus III the Great suffered a crushing defeat from the Romans at Magnesia, starting the unarrestable decline of his kingdom. And when Antiochus IV Epiphanes died in 164 BC internecine conflicts exploded in the royal dynasty, opening the road for Mithridates I' campaigns in his long reign from 171 to 138 BC.

Mithridates I annexed the provinces of Media, Susiana, Persis, Characene, Babylonia and Assyria in the west and of Gedrosia and Sistan in the east, and also took Seleucia on the Tigris, which was the second largest city of Western Asia. The autonomy and Greek institutions of Seleucia was respected. Immediately facing the city, on the left bank of the Tigris, the Parthians founded Ctesiphon, the new capital of the empire. The Seleucids tried with Demetrius II Nicator to reconquered the lost ground, but in 139 BC he lost his battle against the Parthian cavalry and fell into the hands of Mithridates I. The Parthian king treated him gently, also giving him one of his daughter in marriage, but kept him captive in Hyrcania where he remained prisoner till his death. A later attempt in 129 BC to reconquer the former Seleucid dominions by Antiochus VII Sidetes met with no more luck. In this way, Mithridates I created an empire which extended itself from the Euphrates to the Indian Caucasus, which had in itself a vast motley of people and traditions.

Another great king was to prove himself Mithridates II, who went to power about 123 BC. He reported important victories both on the West, where he kept the Seleucids in check, and on the East, where he defeated the the nomad Sakae expanding his power to the Oxus.

Mithridates II was also the first Parthian king to enter in contact with the world's greatest empires, the Chinese and the Roman: around 110 BC Chinese and Parthians both sent embassies to the respective courts with the object of facilitating the commerce with the west. As for the Romans, the first contacts were also friendly since they had a common enemy, Tigranes the Great king of Armenia.