The Fall of the Parthian Empire
The fall of the Parthian Empire was a process that was drawn out over more than two centuries. In its latter decades, it was weakened by dynastic struggles, which exacerbated problems both east and west in an empire that was largely decentralized. In the west, the Parthian problems were directly linked to the demise of the Seleucids, who the Parthians, ironically, helped eradicate in conjunction with Rome.
After their defeat by the Parthians, the Seleucids retreated to Syria where they maintained a rump empire. In the meantime, further west, Rome was on the ascendant, having extinguished Carthage in the Third Punic War, in 146 B.C.E. Thus, simultaneous with the expansion of Parthian power in the ancient Near East was that of Rome in the western Mediterranean area.
However, with Seleucid Syria in the middle to buffer its territory from Rome, the Parthian Empire was seemingly impregnable. To the east, China and Parthia had developed a cordial relationship, including representatives of each kingdom traveling to their counterparts. In fact, by the mid-ﬁ rst century B.C.E., Parthia had control of the Silk Route, from which its treasury derived a great deal of wealth. Then it made a drastic strategic error.
In 69 B.C.E., Parthia entered into an alliance with Rome to attack what was left of the Seleucid Empire. At a time when Parthia’s dynastic struggles were sapping its energy, Parthia and Rome agreed upon the Euphrates River as the western border of the Parthian Empire with Seleucid Syria. However, in 63 B.C.E., the Roman general Pompey the Great conquered the Seleucids once and for all, putting Roman legions on the border of Parthian territory.
The situation in the west remained that way for almost 10 years until the Roman general Crassus invaded the Parthian Empire in 53 B.C.E. The Roman incursion was turned back, but the Romans continued intermittently to pursue their goal of eastern conquest over more than two centuries. Parthia’s wars with Rome abated only during times of Roman political instability, such as the civil wars between the partisans of Pompey and those of Julius Caesar and the one that emerged after the assassination of Caesar, and the Pax Romana.
After 150 years of intermittent warfare between the two empires, most often fought over the strategically important territory of Armenia, Roman emperor Trajan (r. 98–117 C.E.) invaded Parthia in 114 C.E. The reasons for Trajan’s invasion of Parthia have been debated since ancient times. Fame, the reason provided by Cassius Dio, is most often put forth, but modern historians have also asserted that the war was actually started for economic reasons. F. A. Lepper presented French historian J. Guey’s opinion that “Trajan’s real objective in going to war with Parthia was the securing of the overland trade-routes through Mesopotamia” (Lepper 1948, 158).
Whatever the reason, the Roman pretext for war with Parthia was, as usual, a squabble over Armenia; the Parthian emperor had deposed the Armenian king without permission from Rome. Trajan, a former general who led his legions, marched into Armenia virtually unopposed. He then set about conquering upper Mesopotamia and Babylonia. (It is said that when Trajan arrived in Babylon, where he had gone to see the room where Alexander the Great had died, he was disappointed on the pitiable ruin of the city.) In fact, he marched his army to what is now the Persian Gulf.
In 116 C.E., Osroes launched a counterattack and regained some of the territory, while rebellion against the Romans broke out in other provinces. Trajan, in turn, was able to recover Armenia and Mesopotamia, though he lost Assyria. Babylonia was given to Parthamaspates (r. 116 C.E.), a Parthian prince, who served at Trajan’s behest.
Thus, for a brief time there were three kings of Parthia. After Trajan’s death in Anatolia (Asia Minor) in 117 C.E., Hadrian (r. 117–138 C.E.), ascended to the emperor’s throne in Rome. He returned Roman policy to one of peaceful coexistence with Parthia. He also returned the territory Trajan had won to the Parthians.
During the next 50 years, Parthia was at peace with Rome, but its dynastic struggles continued. Nevertheless, in 161 C.E., Vologases IV (r. 148–192 C.E.) took advantage of a temporary dynastic problem in Rome to seize Armenia (which had remained under Roman suzerainty).
Under co-emperors Marcus Aurelius (r. 161–180) and Lucius Verus (r. 161–168), the Romans not only regained Armenia but invaded Ctesiphon. And this time, when they took Mesopotamia, they kept it. In 193 C.E., another Roman civil war emboldened yet another Parthian monarch, Vologases V, who sought to recapture Mesopotamia.
But when the Roman succession question was settled with the accession of Septimus Severus (r. 193–211 C.E.), Parthia’s days were numbered. Severus sacked Ctesiphon in 198 C.E. and returned to Rome with a legendary hoard of gold and silver.
Parthia was impoverished and no match for Rome, but it was not the successors of Septimus Severus who put an end to Parthian rule. Just as Parthia had revolted against Seleucid rule and in time overtook their master, so did the Iranian petty king Ardashir I (r. 208–241 C.E.) attack the weakened Parthian dynasty from his home base of Persis.
The army of Ardashir fought victoriously over the Parthians in 224 C.E. Thereupon, Ardashir easily took Ctesiphon and installed himself as king over what remained of the Parthian Empire and those areas he had conquered beforehand. The new empire became known as the Sassanian Empire, named for the dynasty descended from the Zoroastrian priest Sasan, an ancestor of Ardashir.
However, the Sassanians, themselves, “called their empire Eranshahr, the kingdom of the Aryans; perhaps the Parthians did likewise” (Colledge 1967, 57). Historians have also referred to the Sassanian Empire as the Neo-Persian Empire.