Text by Ilias Anagnostakis.

The Parthian expansion in the 3rd century BC was spearheaded by Arsaces I, who founded the Parthian Empire around 247 BC by revolting against the Seleucid Empire¹. Initially a leader of the Parni tribe², Arsaces I took advantage of the weakened Seleucid control to seize the region of Parthia, situated in northeastern Iran. His successful rebellion against the Seleucid satrap Andragoras marked the beginning of Parthian independence and set the stage for further territorial expansion.

Following Arsaces I, his successor Arsaces II (r. 211–191 BC) continued to fortify and expand the fledgling empire. The Parthians took advantage of ongoing conflicts within the Seleucid Empire, which was grappling with internal strife and external threats, to consolidate their power. During this period, they expanded westward, securing key regions such as Hyrcania and parts of the Iranian Plateau. By the end of the 3rd century BC, the Parthians had established themselves as a formidable power in the region, laying the groundwork for the larger and more sustained expansions that would characterize the 2nd century BC under later rulers like Mithridates I.

The Parthians, from the time of their early expansion (247-240 BC), seem to have had cataphract units, drawing elements from the long-standing cavalry tradition of Central Asia. However, gradually, with their expansion into the Iranian plateau and contact with the excellent Iranian armorers, the Hellenistic Seleucid tradition, the abundant metals of Luristan, and the exceptionally large horses of Media, they were qualitatively and quantitatively upgraded. By 50 BC, they were considered “fully ironclad” as Roman historian Cassius Dio mentioned³ and were a formidable opponent.

Already at Carrhae, in 53 BC, just 1,000 of them (along with 10,000 horse archers) swept away 35,000-43,000 Roman legionaries of Marcus Licinius Crassus. The Parthian general Surena used cataphracts effectively to defeat the Roman forces led by Crassus. Along with Parthian horse archers, played a crucial role in encircling and decimating the Roman legions. Plutarch, in his “Life of Crassus”, describes the effectiveness of the Parthian cataphracts: “The Parthian horsemen wheeled round and round the Romans, shooting their arrows at close quarters, and thus destroying great numbers. Meanwhile, the heavy-armed cavalry, with their spears, rode down and overwhelmed the troops who opposed them.”

In 36 BC at the battle of Urumia, 10,000 of them (along with 40,000 horse archers⁴) destroyed entire sections of the army (180,000 men) of Mark Antony in Media and present-day Kurdistan through countless attacks. They mainly came from the lower aristocracy and their followers, but with the reforms of Artabanus III, other subjects of the state were able to procure the equipment, increasing their numbers. It goes without saying that all members of the royal house of the Arsacids fought as cataphracts.

In the cataclysmic battle of Nisibis, from June 11-12, 217 AD, they reached the astonishing number of 30,000(!) men (in an army of 130,000) and, charging at 20-30 km per hour in very dense formations, put the gigantic (110,000 strong) Roman army in a very difficult position. This battle between the Parthians and the Roman Empire saw the extensive use of cataphracts by the Parthians. “The Parthians, too, had numerous horsemen equipped with long lances and fully protected by armor, both men and horses alike. They charged the Roman lines repeatedly, causing great confusion and slaughter.” (Cassius Dio) Though the battle ended inconclusively, it demonstrated the significant role of heavily armored cavalry in Parthian military strategy.

Of course, the tradition and use of cataphracts were adopted in their entirety by the Sassanids, as well as by the Romans, particularly by Constantius II (337-361 AD), who established “countless” regiments. At the Battle of Edessa (260 AD) the influence of Parthian military traditions, including the use of cataphracts, was evident. The Persian forces, including cataphracts, captured the Roman Emperor Valerian, showcasing their effectiveness in battle. “The Persian army, including the heavily armored cavalry units known as cataphracts, surrounded the Roman legions. The Romans, unable to withstand the continuous assaults, were eventually overwhelmed, leading to the capture of Emperor Valerian.”⁵

Another example is the Battle of Callinicum (296 AD) where the Parthian cataphracts were instrumental in the conflict against the Roman Empire. The engagement highlighted their strategic importance and the continued legacy of Parthian cavalry tactics even as the political landscape evolved. “The Sassanian forces, inheriting the tactics of their Parthian predecessors, deployed their cataphracts with great skill, causing heavy casualties among the Roman ranks. These heavily armored horsemen were pivotal in breaking through the enemy lines.”⁶

1. Greek power in West Asia during the Hellenistic period. Founded in 312 BC by the Macedonian general Seleucus I Nicator, the empire emerged after the division of the vast territories conquered by Alexander the Great. ↩︎
2. East Iranian people who lived around the Ochus river, southeast of the Caspian Sea. ↩︎
3. Roman History, 23.9. ↩︎
4. The numbers may have been inflated but nevertheless, they show that the sizes of the armies and the divisions of the cataphracts were significant. ↩︎
5. Zosimus, “New History”. ↩︎
6. Ammianus Marcellinus, “Res Gestae”. ↩︎