Originally a Scythian group from Central Asia, the Arsacids, known in the Greek and Roman accounts as the Parthians, founded a powerful empire that at its zenith ruled a vast territory stretching from Central Asia to Syria and from Armenia to the Persian Gulf. The armies of the Arsacid (Parthian) Empire (r. 247/238 BCE–224 CE) were some of the most accomplished, efficient, and feared of all military forces of antiquity. Raised from a young age to the arts of horsemanship and archery, Parthian soldiers enjoyed a reputation that still echoes today in the modern Persian term pahlavan, meaning “champion” or “warrior” (Shahbazi: “Army I”). Parthian military tactics and sharpshooting are renowned in military history. Because of the geographical location of their empire, the Parthians were forced to fight frequently against various nomadic groups invading from Central Asia as well as against Roman legions attacking through Armenia or Mesopotamia. To neutralize these threats to the security of their empire, the Parthians were forced to develop a highly flexible and elastic military force that could employ exceptional mobility and effectiveness.
Our information about the Arsacid army is extremely scanty. We do not know the exact size, internal organization, and social composition of Arsacid armies. Lack of adequate sources has forced scholars to rely almost exclusively on Roman and Greek accounts, which are characterized by hostility and disdain toward these eastern neighbors of Rome, denouncing the Arsacids as treacherous and arrogant barbarians with strange and repugnant customs and practices. This negative image was manufactured and promoted by the Romans, who were skilled political propagandists against enemies who stymied Rome’s expansionist policies. The deep hostility and resentment expressed toward the Arsacids originated from the failure of Rome to subdue these uncanny Iranians who refused to be intimidated and submit to the might of Roman legions and had repeatedly displayed an exceptional talent and brilliance in defeating Roman armies. As Emperor Julian wrote, “tell me why, after a war of more than three hundred years, you Romans have never conquered a small province beyond the Tigris which is still governed by the Parthians? Shall I tell you why? It was the arrows of the Persians that checked you. Ask Antony to give you an account of them, since he was trained for war by you” (Julian: 387).
The Arsacid monarchs ruled a highly decentralized empire. When an Arsacid king had to raise an army, he asked the local kings, vassals, governors, regional magnates, and tribal chiefs under his suzerainty to mobilize their forces, which included their families, dependents, servants, and slaves, and lead them to a designated meeting place. Depending on the movement of enemy forces, the king divided these units into a number of smaller armies, each responsible for confronting the enemy as it entered Parthian territory. The cavalry constituted the backbone of the Arsacid army. According to Justin, the Arsacids refused to engage their enemy in hand-to-hand combat, and they avoided “close fight” at all costs (Justin: XLI.2.2–3). They always fought “on horseback, sometimes advancing, and sometimes turning back upon their enemies” (Justin: XLI.2.2–3). The Parthians were “armed like the Scythians” from whom they had “descended” (Justin: XLI.2.2–3). A section of the Arsacid cavalry was armed with bows and arrows, while other units, namely the cataphracts, were heavily armed with lance, knife, and bow, with both horse and cavalryman armored and protected by coats of chain mail. When the Arsacid commander Surena (Suren) defeated the Roman army under the command of Crassus in the Battle of Carrhae in 53 BCE, his army was composed of 10,000 cavalry. In the confrontation with Mark Antony in 36 BCE, the Arsacid cavalry was estimated at 50,000, with 400 members of the nobility constituting the core of the cavalry forces (Justin: XLI.2.2–3). The Arsacid nobility constituted the highest echelon of the Parthian military forces, which also included their dependents, servants, retainers, serfs, and at times foreign mercenaries. According to Justin, the Arsacids did not have an army composed “wholly of free men,” but the majority consisted “of slaves” whom they brought up “with as much care as their children, and [they] teach them with great industry, both riding and shooting” (Justin: XLI.2.2–3). Justin erroneously equated the Parthian nobles known as āzāt with “free-men” and the large army of their dependents with “slaves.” Arsacid units included infantry divisions as well, but these numbers were small, and their role and impact on the battlefield were negligible.
The Arsacid elite dressed like the Medes, with a garment translucently thin and fluent (Justin: XLI.2.2–3). The Arsacid cavalry wore helmets and breastplates of rawhide or steel, which according to Roman observers blazed like fire under the sun. Their horses were likewise described as wearing plates of bronze and steel (Justin: XLI.2.2–3). Parthian fighters painted their faces and gathered their hair “in a mass upon their foreheads after the Scythian mode” (Plutarch: 1.814). They attacked the enemy with long spears, lances, and pikes or from a distance by shooting extremely swift arrows with their strong bows. To the shock of their enemies, the barbed arrowheads pierced through hard and soft armor, inflicting severe damage on veins and muscles. The Parthian cavalry was known for the unique and exceptional ability of its horsemen to shoot arrows as they fled, an old and extremely difficult technique known as the “Parthian shot.”
The Parthian strategy was to fight with patience, astuteness, and minimum hand-to-hand contact with the foe, demoralizing the enemy instead with random unpredictable and shocking moves, such as appearing and disappearing, hitting and escaping, and retreating and encouraging pursuit but then suddenly turning back and attacking with a shower of arrows. Parthian archers had at their disposal a large number of camels loaded with arrows and standing on the fringes of the battlefield to deliver new supplies of ammunition (Plutarch: 1.815). The Parthians did not use war chariots. Instead of using horns or trumpets to sound the attack, the Parthian armies used hollow drums of animal hide to which they had attached bronze bells. The beating of these drums all at once across different parts of the battlefield produced a most eerie and terrifying sound, which according to Roman sources sounded like the roaring of wild animals accompanied by claps of thunder (Plutarch: 1.814; Justin: XLI.2.2–3). Parthian armies also resorted to psychological warfare as well as negotiations to deceive the enemy and force its leadership to surrender. Even after defeating a formidable foe, they did not make any attempt to continue pursuit at night, preferring to finish the job at dawn the following day (Plutarch: 1.819).
The brilliance of the Parthian cavalry on the battlefield and the defeats they inflicted on Rome at military encounters such as the one at Carrhae in 53 BCE forced some Roman writers and historians to admit grudgingly that the Iranian dynasty constituted a formidable adversary worthy of Rome’s respect and admiration. For example, the Roman consul and historian Cassius Dio wrote that “They [Parthians] are really formidable in warfare. … The Parthians make no use of a shield, but their forces consist of mounted archers and lancers, mostly in full armor. Their infantry is small, made up of weaker men; but even these are all archers. The land, being for the most part level, is excellent for raising horses and very suitable for riding about on horseback. … [E]ven in the war they lead about whole droves of horses, so that they can use different ones at different times, can ride up suddenly from a distance and also retire to a distance speedily” (Cassius Dio: XL.14–16).
Recognizing the devastation wrought by war and its destructive impact on their economy and population, Parthians displayed a genius for negotiating peace treaties. Contrary to their claims of superiority over the so-called barbarians, Romans who had suffered military defeats at the hands of the Parthian forces also strove to avoid dangerous wars, which only resulted in disgraceful peace treaties. The Parthian armies carried numerous colorful flags and banners onto the battlefield. These were often adorned with the figures of animals, including dragons and lions, but the ancient national emblem of Iran, the jewel-encrusted Derafsh-e Kavyan (Standard of Kaveh) served as their imperial flag (Shahbazi: “Army I”).
Bivar, A. D. H. “The Political History of Iran under the Arsacids.” In The Cambridge History of Iran, Vol. 3(I), edited by Ehsan Yarshater, 21–99. Cambridge: Cambridge University Press, 1983.
Cassius Dio. Dio’s Roman History. Translated by Earnest Cary. London: William Heinemann, 1928.
Colledge, Malcolm A. R. The Parthians. New York: Praeger, 1967.
Julian. The Works of the Emperor Julian: The Caesars. Translated by Wilmer Cave Wright. London: William Heinemann, 1913.
Justin. The History of the World. Translated by G. Turnbull. London: Printed for S. Birt and B. Dod, 1746.
Plutarch. Fall of the Roman Republic. London: Penguin, 1972.
Plutarch. Lives. 2 vols. New York: Barnes and Noble, 2006.
Rawlinson, George. The Sixth Great Oriental Monarchy. Tehran: Imperial Organization for Social Services, 1976.
Schippmann, K. “Arsacids.” Encyclopaedia Iranica, 1986, http://www.iranicaonline.org/articles/arsacids-index#pt2.
Shahbazi, A. Sh. “Army I: Pre-Islamic Iran.” Encyclopaedia Iranica, 1986, http://www.iranicaonline.org/articles/army-i.
Strabo. The Geography of Strabo. Translated by Horace Leonard Jones. London: William Heinemann, 1930.