ancient Iran The end of the Parthian empire (162-226) also known as Persia

The 40 years’ peace was succeeded by almost uninterrupted hostilities with Rome, with varied success; Parthia was more vulnerable because of the exposed position of its capital.

The reigns of Vologeses III (or II; c. 105/106–147?) and especially Vologeses IV (or III; 148–192), the latter not having to dispute the throne with a pretender, could by their lengths be a sign that the country might have experienced a certain stability. But underneath the apparent calm the intrigues continued, with Rome receiving embassies from the Hyrcanians, the Bactrians, and doubtless from the Kushān.

A new clash with Rome came in 161, this time on the initiative of Vologeses IV (or III), who considered himself strong enough to attack. He occupied Armenia, crossed the Euphrates, and invaded Syria, which for two centuries had not seen Parthian cavalry. And, although the country had been Roman since the time of Pompey, the Syrian population, which included Jews driven from Palestine by the Romans, received the Parthians as liberators. The situation became so serious that Lucius Verus, co-emperor with Marcus Aurelius, was dispatched to the east with strong reinforcements taken from the fronts on the Danube and the Rhine. The Romans retook Armenia (163) and succeeded in a campaign similar to Trajan’s: Dura-Europus was taken and remained Roman until its destruction by the Sāsānids; Seleucia on the Tigris, despite the welcome it reserved for the Romans, was sacked; and in 164 or 165 for the second time Ctesiphon fell into the hands of Romans, who razed the royal palace.

Once more success was not continuous. The Roman army had come from Armenia and crossed through Azerbaijan, where it was exposed to plague. Contaminated, the Roman army was sorely tried by disease and obliged to retreat, but not definitively. Lucius Verus, repeating his campaigns in Armenia and northern Mesopotamia, inflicted heavy losses on the Parthians.

The tensions between the two states did not diminish when Vologeses V (or IV; reigned 191–208/209) supported a pretender (Pescennius Niger) against Septimius Severus. The latter became emperor in 193 and began operations that permitted him to occupy first northern and then southern Mesopotamia and, for the third time in a century, Ctesiphon. The Parthians in their retreat adopted a scorched-earth policy. As under Trajan, the starving Roman army went back up the Tigris, failed in its attempt to take Hatra, and left the country.

Vologeses VI (or V), son of the previous king, succeeded him (reigned 209–c. 222), but his throne was contested—and the empire divided (see below)—from 213 on by another prince, Artabanus V (c. 213–224), who was able to maintain his claim with the support of the kingdom of Media (see table for chronology). A new Roman invasion of Mesopotamia took place under Caracalla, the casus belli being the refusal of Artabanus V to give Caracalla his daughter in marriage. The young emperor dreamed of rebuilding Alexander’s empire but succeeded only in pillaging Media and destroying the hypogea of the Arsacid kings at Arbela. The Parthian reply was harsh. Artabanus avenged himself by invading the Roman provinces and destroying several cities. Rome sued for peace. Artabanus’s conditions were too hard and were refused. Hostilities were taken up again and once more turned in favour of the Parthians, who were so successful that the emperor Macrinus paid a large sum to make peace.

Since 208 Pāpak (Bābak), a lesser prince of Persis, had been preparing a revolt, which his son Ardashīr I finally declared openly. A battle took place between him and Artabanus V in 224; the Parthian was killed, and the throne of Iran passed into the hands of the Sāsānids, a new dynasty, originally from Fārs, the cradle of the Achaemenids.

The Iran of the Parthians—in the middle between the Romans in the west and the Kushān in the east, a region strategically crucial for international commerce—maintained open roads, created cities, and encouraged exchanges that were the lifeblood of this great empire stretching from the portals of China and India to the Roman Empire. Tolerant in religion, it was Parthia that contributed to the dissemination of Buddhism to China, where a Parthian prince spread the word of Buddha near the mid 2nd century ad. For nearly half a millennium Parthia pursued its great ambition to recover the western provinces of the Achaemenids. Undermined by internal weaknesses, Parthia finally succumbed, leaving its great dreams to its successors, the Sāsānids.