|Previous: Pyrrhic War|
|Concurrent: Wars of the Diadochi, Roman Conquest of Greece|
|Next: Scytho-Parthian Wars|
|Date: 268-263 BC|
|Place: Armenia, Azerbaijan, Georgia, and northwestern Iran|
|Outcome: Parthian victory|
The Parthian Empire was once a part of the Dahae Confederacy in the Middle East, but later broke off and founded their own empire. Their main bases were Susa and Arsakia in Persia and Campus Sakae in Tribus Sakae, and their main threats to expansion were the powerful Hellenic Seleucid Empire and the Artaxiad Empire of Armenia. The Greeks bordered them to the west; they were old-fashioned people who used phalanxes, centuries-old tactics. The Armenians were mountainous peoples with no experience in the desert wars. The Parthians' king Arsaces and his sons built an empire on their wealth but required additional subjects to pay off the debts that they owed moneylenders for troop costs, and got an excuse for war when an army of Armenians under Rimsin of Arsamosata encroached in their turf in 268 BC.
The Parthians, led by Arsaces and his sons Achaemenes and Ardumanish, destroyed the Armenian army using surprise to their advantage, with their Cataphracts proving key to the victory. The Armenians retreated to a fort, where they remained, not attempting to take the unoccupied Arsakia. After this victory, however, Arsaces died, leaving his empire to Ardumanish. Ardumanish was an adept commander and talented king, leading his armies in person. He reformed the army in his own way, which facilitated troop mobilization; he would recruit Cataphracts and horse archers from his own ranks, while they recruited local Eastern Infantry spearmen as mercenaries, to be disbanded when necessary. Ardumanish also preferred to rely on long sieges, building equipment while the siege was going on so that the garrison would be starved of supplies before the assault, and he assaulted with his engines as the garrison was suffering.
In 267 BC, the Parthians invaded Atropatene, taking Phraaspa from the Armenians, who were enslaved by the Parthians, spreading them in governed settlements across their empire. The city was used as a staging point for forays into Armenian turf by the Parthians, who used it as a center for the recruitment of Hillmen. In 265 BC, the city of Artaxarta, in Armenia, fell to the Parthians, who massacred 36,000 people in response for the city's defiance, inflicting heavy casualties on the Parthians before the walls were captured.
In 263 BC, the Armenians attempted to send the Parthians a ceasefire message. When they refused to pay 3,000 denarii each year for five years (the span of the war so far) as tribute, the Parthians invaded Colchis, and Kotais fell to the Parthians, and 1,781 Armenians were enslaved. The capture of Colchis ended the war, with the Artaxiad Empire falling to the Parthians.