Chapter Seventeen – From the Reign of Phraates IV to Vonon I of the Arsacid Dynasty of Parthia

Phraates IV

The preceding chapter concluded with King Orodes II of the Arsacid dynasty in deep mourning over the battlefield death of his son and crown prince, Pakoros, at the hands of Publius Ventidius, a highly capable lieutenant of Marcus Antonius (Marc Antony). Despite his profound grief, Orodes eventually recovered his composure. Following consultations with the Parthian Senate—an assembly of high-ranking nobles and clan leaders—he appointed his son, Phraates IV (Φραάτης), as his successor.

According to several Greco-Roman sources, including Justin (Epitome of Pompeius Trogus, 42.1–2), Cassius Dio (Roman History, 49.23), and Plutarch (Antonius, 38–41), Phraates IV ascended the throne in 37 BCE through a campaign of violence and treachery. These accounts allege that Phraates not only murdered his own father, Orodes II, but also systematically eliminated all his brothers. Some of these half-brothers were the sons of Laodike (Λαοδίκη), daughter of Antiochus I Theos of Commagene, a Greco-Iranian noblewoman of royal lineage. As descendants of Hellenistic kings, their maternal ancestry was perceived by many within the Parthian Senate as granting them a superior claim to legitimacy.

Cassius Dio reports that Phraates, fearing a backlash from the noble council and the potential elevation of one of his half-brothers, ordered their execution. In an even more extreme act of dynastic paranoia, he is said to have murdered his own teenage son, suspecting that the Parthian Senate might favor the boy as a more moderate and legitimate ruler.

Dio writes:

“Orodes, overcome by grief at the death of Pakoros, eventually died. But before his death, he had transferred power to Phraates, who proved himself the most impious of men. He killed the sons of Antiochus’s daughter because of their noble maternal ancestry, and when Antiochus resisted, he murdered him as well. He then turned on many of the most honorable men of the realm, committing widespread atrocities. As a result, many of the leading nobles abandoned him and fled the kingdom; one among them, Manases, sought refuge with Antonius.”

While Roman authors frequently depicted fratricide as an institutional characteristic of Arsacid succession, such generalizations demand skepticism. Had dynastic fratricide truly been a regularized custom, the noble houses—particularly the mothers and protectors of these princes—would likely have devised mechanisms to prevent or preempt such purges. Many of these princes were adults, capable of rallying supporters or seeking asylum with neighboring powers. Although acts of bloodshed during succession crises were not unheard of, it is improbable that such violence was accepted as a constitutional norm within the Parthian Senate or noble council.

This narrative tendency reflects the familiar Greco-Roman trope of portraying the East as despotic and cruel. Iranian rulers were often depicted as barbaric "others," serving as a foil to the supposed virtue of Roman political order. Unfortunately, the Zoroastrian clergy of the later Sasanian period contributed to the loss of indigenous Parthian records, rendering modern scholars largely dependent on hostile Roman sources. Until further archaeological or epigraphic evidence emerges, these accounts—however detailed—should be approached critically and with due caution.

Plutarch adds:

“Phraates murdered his father Orodes and usurped the throne. Many Parthians fled in great numbers, especially Manases, a man of exceptional valor and stature, who sought asylum with Antonius. Antonius compared him to Themistocles, lavished him with honors, and granted him control of Larissa, Arethousa, and Hierapolis—the last of which was formerly called Bambyce.”

Plutarch reports that Marcus Antonius viewed the defection of the Persian nobleman Manases as analogous to the legendary flight of Themistocles from Athens to the Achaemenid court of Artaxerxes I. Hoping to exploit Manases’ strategic knowledge in an impending campaign against Parthia, Antonius appointed him governor over three prominent cities on the Syrian littoral of the Mediterranean: Larissa, Arethousa, and Hierapolis (Bambyce).

Yet, when Phraates IV extended an offer of peace and reconciliation to Manases, Plutarch states that Antonius, eager to gain a diplomatic advantage, feigned acceptance. To project goodwill, he returned Manases to Phraates. In exchange, Antonius requested that the Parthian king restore the Roman military standards (signa) and eagles (aquilae) captured during the catastrophic defeat of Marcus Licinius Crassus at Carrhae in 53 BCE. Antonius also demanded the release of the remaining Roman prisoners still held in Parthian custody—a request laden with political symbolism, as these remnants of Crassus’s army represented not only a humiliating loss but also a living stain on Roman virtus.

Phraates, however, refused to return either the captives or the captured standards. His silence was calculated, and his intransigence underscored the profound psychological and geopolitical significance of Crassus’s defeat, which had become a festering wound in the Roman imperial psyche. As the historian A.D.H. Bivar has noted, the loss of Roman standards to Parthia was not merely a military misfortune; it constituted a profound rupture in the myth of Roman invincibility, triggering successive efforts by Rome to redeem its prestige through renewed campaigns into the East.

Indeed, the continued possession of these sacred symbols by the Parthians did more than remind Rome of its vulnerability; they incited a complex interplay of shame (pudor) and wounded pride (superbia) within both Roman political culture and imperial propaganda. For the Parthians, the standards symbolized not merely victory, but undeniable superiority over the world’s most powerful state.

This deep humiliation found voice in the literature of the Augustan age. The Roman poet Horatius (Horace), in his Carmen Saeculare—commissioned by Octavianus (later Augustus Caesar), Antonius’s archrival—articulates Rome’s desire for revenge and redemption. In the fifth stanza, he invokes divine sanction for imperial expansion:

Like Jupiter in heaven, Augustus on earth Is now a god eternal; destined, he shall bring Britain and Persia under Roman rule. But oh! what shame— Not yet avenged is Crassus, the Cēnite, Whose legions lie with barbarian brides, Forgetting Rome, forgetting Vesta’s sacred hearth. This is not the mark of those who made Rome great.

Elsewhere in the Odes (2.2 and 3.5), Horace explicitly refers to the defeats at the hands of Pakoros and Manaios, lamenting the loss of honor and the standards that once symbolized Roman dominion:

Twice has Pakoros and Manaios Shattered our proud legions, And with mocking laughter They added our eagles to their scanty treasure.

The Elegies of Sextus Propertius also echo this longing for vengeance and restoration. In a stirring vision of Roman resurgence, he writes:

The Tigris and Euphrates flow at your command. Yet still Parthia defies our scepter. Let them learn to bow before the Latin Jupiter! March onward, soldiers! Raise your sails— Let your armored cavalry thunder across the plain. Let the mourners of Crassus become the heralds of Rome’s revenge! By Father Mars and the sacred fires of the Asavan Vesta, Let me live to see Caesar’s triumph, His chariots glistening with Eastern gold, His steeds led to the cheers of the Forum Romanum! Let me gaze on cities taken, Bows and bridles torn from fleeing Parthians, Their generals in chains beneath the axes of Rome.

Likewise, Publius Vergilius Maro (Virgil)—writing in the Aeneid under the patronage of Augustus—sang of a new Roman destiny that would stretch to the ends of the East:

Overcome the Hyrcanians and the swarthy Arabs, To the dawn-lit borders of India, To recover the standards lost to the Parthians, Praying to Mars before the twin Gates of War.

Even Ovid, in his Ars Amatoria and Fastorum Libri Sex, alludes to Rome’s unhealed trauma. Referring to the death of Gaius Caesar, Augustus’s grandson, who died during preparations for a Parthian campaign, Ovid recalls Rome’s yearning for retribution:

From joy to sorrow, our festivals falter— Crassus lost his standards, his son, and his army to the Euphrates. He himself was slain. “Hail, Parthia!” cried the gods, “But not forever. You must return the falcons! Vengeance shall come for the blood of Crassus!”

Antony’s Campaign Against Parthia

Marcus Antonius (Mark Antony), in an effort to strengthen his political alliance with Gaius Octavius (Octavianus), had married Octavia, the emperor’s sister. Yet soon disillusioned by this union, he fell under the powerful sway of Cleopatra VII Philopator, queen of Egypt. It was Cleopatra—ambitious, calculating, and determined to secure a kingdom for her son Ptolemy XV Kaisarion, whom she claimed as the son of Gaius Julius Caesar—who financed much of Antonius’s eastern campaign against Phraates IV and the Parthian state.

In preparation for this grand invasion, Antonius dismissed Cleopatra, who had joined him in Syria, back to Egypt, and began organizing his own forces as well as those of local allies. Chief among these was Artavasdes II, king of Armenia, who pledged 6,000 cavalry and 7,000 infantry in support of the Roman effort.

In the spring of 36 BCE, Mark Antony marched from Zeugma toward Melitene (Malatya) and proceeded along the Euphrates toward Satala in Armenia Minor. His army numbered approximately 60,000 Roman legionaries, supplemented by 10,000 Gallic and Spanish cavalry. Despite Armenia being nominally a Roman ally, Antonius initially invaded it—motivated, according to Florus, by a desire to add the Araxes and Euphrates rivers to the list of victories inscribed on his statues and triumphal dedications.

According to Plutarch, Antonius, intoxicated by his passion for Cleopatra, was eager to conclude the war swiftly and return to her. This infatuation, coupled with overconfidence, resulted in a hasty and ill-conceived campaign. Rather than resting his exhausted troops in Armenia over the winter, he pressed on into Media Atropatene (modern-day Iranian Azerbaijan), thereby exposing his forces to logistical hardship and resistance from a well-prepared enemy.

As the Roman columns advanced deeper into Atropatene, local opposition stiffened. The Medes of Atropatene, alongside Parthian detachments, mounted increasingly aggressive resistance. Antonius had also committed a strategic blunder: he had left behind his siege engines—battering rams, stone-throwers, and catapults—entrusted to Oppius Statianus, one of his commanders, who was bringing them forward more slowly in a separate convoy of 300 carts.

Antonius had underestimated both the terrain and the enemy’s capacity for rapid counterattack. His calculation—that speed would substitute for siege equipment—proved disastrous. The forests of Armenia and Media, unlike those of Gaul or Italy, lacked the long, durable timber required to rebuild these heavy machines should they be destroyed.

Parthian scouts monitored the Roman movements closely. It is likely that Phraates IV, in coordination with both Artavasdes of Armenia and Artavasdes of Atropatene, made plans to entrap the Romans. These eastern kings, both bearing the same name and acting as local sovereigns, would prove to be less reliable allies than Antonius had hoped.

When Antonius arrived at Phraaspa—capital of Atropatene, near modern-day Tabriz—he was without his siege engines. To compensate, his soldiers began constructing an assault mound against the city's walls. The task was slow and manpower-intensive, especially as Median resistance stiffened.

Sensing opportunity, Phraates IV arrived with fresh forces. Learning from his scouts that Statianus was bringing the siege convoy, he immediately dispatched a strong cavalry unit of archers and javelin-throwers to intercept it. During the engagement, the Armenian cavalry who had accompanied Statianus deserted under the pretense of offering aid, leaving the Roman detachment vulnerable. The Parthians, with their superior mobility and lethal missile tactics, annihilated the convoy, destroyed the siege engines, and captured many Roman troops. The remaining supplies were burned or plundered.

When word of this catastrophe reached Antonius, Artavasdes II of Armenia had already withdrawn his troops and returned to his kingdom. Cassius Dio records that Statianus appealed to Artavasdes for reinforcements, but the Armenian auxiliaries—perhaps deliberately—arrived too late. Dio writes:

“When he [Artavasdes] came upon the scene, he found nothing but the dead.”

Statianus took his own life, and two full Roman legions were destroyed in the engagement. Among the captives was Polemon I, king of Pontus and an ally of Antonius, who secured his release only by paying a substantial ransom.

According to Dio, upon hearing of the defeat and learning that Polemon had been captured, Artavasdes and his Armenian forces—terrified by the ferocity of both the Parthian and Median warriors—fled through the Sahand Mountains, back to Armenia. It is plausible that this retreat had been prearranged under a secret treaty between Artavasdes and Phraates IV.

Plutarch confirms the morale collapse in the Roman camp, writing that:

“The Parthians now, with gleaming ranks and terrifying cries, surrounded the Romans and made them appear ridiculous in their confusion and shame.”

Antony’s Retreat from Persia

According to Cassius Dio, when the troops of Phraates IV clashed with those of Oppius Statianus, the Roman commander appealed to Artavasdes, the king of Armenia—who was still accompanying Antony—for reinforcements. However, Artavasdes’ auxiliary forces, whether by negligence or design, arrived too late. Dio records that by the time Artavasdes and his men reached the battlefield, “they found nothing but dead bodies,” for the Parthians had already inflicted a crushing defeat. Statianus took his own life, and many of his troops were either killed or captured. Three hundred Roman wagons, loaded with siege engines such as battering rams and carinae, were surrounded and destroyed. Two Roman legions were annihilated, and many soldiers were taken prisoner, including Polemon, king of Pontus—an ally of Antony—who, according to Dio, bought his freedom with a large ransom.

Near the salt flats of Lake Urmia, at Phraaspa, Artavasdes and his Armenian troops—unnerved by the fearsome warfare of the Median Atropatene and Parthian forces—lost their morale upon hearing of Polemon’s capture. They withdrew from the heights of the Sahand mountains and returned to Armenia. Some speculate that Artavasdes’ retreat may have been prearranged, based on a secret agreement with Phraates IV. According to Plutarch, the Parthians, now emboldened, surrounded the Roman forces with dazzling formation and inflicted humiliation on them with their fearsome presence.

Cassius Dio reports that Antony, in an attempt to negotiate peace, dispatched envoys to Phraates IV. Seated on a golden throne, Phraates received them in an unusual manner: throughout their discussions, he repeatedly pulled and released the string of his bow, producing a deliberate, ominous sound. This symbolic gesture, given that the bow was a traditional emblem of Parthian kingship (depicted on the reverse of many Parthian coins), conveyed an unmistakable message—peace would be offered on Parthian terms, under the shadow of their military strength.

Initially, Phraates rebuked the envoys for Antony’s arrogance in sending an embassy without proper deference. He then softened his tone, yet continued the symbolism of drawing the bowstring. Plutarch notes that Antony had asked for the return of Rome’s captured standards and military insignia: those taken from Crassus at Carrhae, others seized by Pacorus in Syria, and those lost in Statianus’s defeat. Antony sought to reclaim these symbols to save face upon his return to Rome. But Phraates, fully aware of their psychological value, declined. Instead, he promised Antony safe passage for his retreating army—adding that this outcome was far better than Crassus’s disastrous end.

After receiving his envoys’ report, Antony feared that any show of desperation might provoke further Parthian aggression. Following Dio’s account, Antony abandoned the siege of Phraaspa and pretended to act as if among friends. But the Atropatenes, determined to punish Roman aggression, launched a surprise attack: they surged from behind the city walls, burned the Roman siege mound, and destroyed Antony’s remaining equipment. Meanwhile, the Parthians raided the Roman camp, killing many soldiers. Shocked and weakened, Antony was forced into a hasty retreat.

During the retreat, according to Plutarch and Dio, the Roman army was harassed daily by Parthian attacks. One of Antony’s commanders, Flavius Gallus, attempted a bold maneuver to delay the Parthian pursuit—but paid with his life. Gallus was struck with four arrows and died from his wounds. Over 3,000 Roman soldiers perished in that battle, and another 5,000 were wounded in their tents. Plutarch writes that Antony, weeping, visited the wounded to offer comfort. The Parthians, reinvigorated by their victories, spent the night near the Roman encampment, hoping to plunder it at dawn. By morning, another Parthian force—said to number 40,000—arrived to join the assault.

Meanwhile, famine struck Antony’s army. With their food supplies dwindling, even the hard-won grain was of little use, as there were no mills to grind it. Most of the cattle needed to power the mills had been killed or repurposed to carry the wounded. In desperation, soldiers consumed roots and wild grasses—some of which drove them mad or proved fatal. Despite their suffering, Parthian cavalry continued to pursue and harass the retreating Romans, day after day.

Finally, Antony’s army reached the Aras River, the frontier between Atropatene and Armenia. According to Plutarch, as the Romans reached the river, the Parthians—exhibiting their Mithraic creed—ceased hostilities. They lowered their bowstrings and bid the Romans a safe journey. The exhausted Romans, unable to believe that the danger had passed, embraced one another in disbelief and wept with relief. Antony conducted a headcount: he had lost twenty thousand infantry and four thousand cavalry.

The Roman troops, furious with Artavasdes of Armenia for abandoning them at Phraaspa, urged Antony to punish him. But Antony, lacking strength and supplies, instead chose diplomacy. Artavasdes supplied him with provisions—purchased using funds sent by Cleopatra. According to Cassius Dio, Antony flattered Artavasdes and convinced him to allow the Romans to winter in Armenia, promising a renewed invasion of Parthia in the spring and a share of future spoils. Nevertheless, the army suffered another eight thousand deaths from the harsh Armenian winter.

Eventually, Antony reached Syria, where Cleopatra met him near Sidon with a fleet of ships and new supplies. She clothed the survivors and took them back to Egypt. Soon after, Antony returned to Nicopolis in Armenia to apprehend Artavasdes. He sent Quintus Dellius with numerous promises to lure Artavasdes to a meeting under the pretext of planning another campaign against Persia. But Artavasdes, sensing the trap, refused. Antony then marched on Artaxata, the Armenian capital. Realizing he had no alternative, Artavasdes came to meet him—and, as he feared, was immediately imprisoned. As Cassius Dio records:

He initially arrested Artavasdes without placing him in fetters and took him along to the fortresses where the Armenian royal treasures were stored, hoping to acquire the wealth without resorting to force. Antony justified this action by claiming he had no intention of humiliating the king, but merely sought to compel the Armenians to pay a ransom for having granted refuge and support to their monarch. However, when the custodians of the royal treasuries showed no sympathy for their king, and the Armenians—who were already at war with him—proclaimed his eldest son, Artaxias (Artaxes), as the new king, Antony decided to bind Artavasdes in silver chains, declaring it inappropriate to bind a man who had once been king with iron shackles.

Antony subsequently subdued the entirety of Armenia, bringing some regions under his dominion through military conquest and others through diplomatic means. Artaxias, following a severe defeat in battle, fled and sought protection from the king of Parthia. As Plutarch recounts, Antony—seeking to exaggerate his triumph and divert attention from his greater failures in Parthia—brought Artavasdes in ceremonial captivity to Alexandria, parading him in a theatrical spectacle meant to mimic a Roman triumph.

According to Cassius Dio, following the Armenian defeat, Artaxias took refuge with the Parthian king Phraates IV, who at the time maintained a cautious yet opportunistic relationship with Rome. To solidify his eastern alliances, Antony arranged a marriage between his son and a daughter of the Median king. Plutarch, however, states that Antony also considered proposing a daughter of Phraates himself as a bride for his son, a gesture aimed at cementing ties with the Parthian royal house and its powerful senate of nobles.

Nevertheless, despite these gestures of diplomacy, Antony never again dared to launch a campaign into Parthian territory. Even during moments of internal Parthian unrest—such as the rebellion of Tiridates against Phraates IV—Antony refrained from intervention, constrained by his earlier humiliations and the formidable resistance of both the Parthian army and its aristocratic institutions.

The Revolt of Tiridates and the Scythian Support for Phraates IV

Isidore of Charax records two revolts against King Phraates IV of Parthia. According to Roman sources, the principal rebel leader, Tiridates (in today's Persian Tirdat), with the diplomatic backing of Caesar Augustus, managed to temporarily drive Phraates from the Parthian capital, forcing him to seek refuge among the Scythians. The Scythian king—though unnamed in extant sources—remained steadfastly loyal to Phraates and provided him with military support, enabling the Arsacid monarch to reclaim his throne.

Although the precise identity of the Scythian ruler is obscure, it is probable that he governed the Saka-Scythian groups who had migrated into eastern Iran, particularly into the region of Sakastan (modern Sistan), following their displacement by the Yuezhi from their ancestral homelands in Central Asia. These Scythian tribes had gradually settled in the territories of the former so-called Greco-Bactrian Kingdom, a region that had come under the sway of the emerging Kushan power by the early 1st century CE. Greek and Roman authors often refer to this syncretic polity, which maintained significant Hellenistic cultural elements, as the “Greek kingdom of Bactria.”

The Saka-Scythians had been integrated into the Parthian imperial system as early as fifty years before Isidore's account, and their migration into the Helmand Basin and adjacent areas occurred with the tacit approval—or even logistical support—of the Arsacid monarchs. Since their settlement, these groups had developed a complex but generally loyal relationship with the Parthian state. Their tribal leaders, while maintaining considerable local autonomy, acknowledged Arsacid suzerainty, and their military contingents proved valuable to Parthian campaigns in the East and West.

Indeed, Indian historical sources testify to the extent of Indo-Parthian dominion in the early 1st century CE, especially under the rule of Gondophares (c. 20–60 CE). Indo-Parthian power extended from Arachosia (Kandahar) and Sakastan through western Punjab and deep into the lower Indus Valley. These sources describe a multicultural polity populated by Scythian nomads, Greek-descended Yavanas, and Pallavas, many of whom would later participate in southern Indian conflicts over the next two centuries. It is highly plausible that elements of these Indo-Scythian lineages were among those who rendered decisive support to Phraates IV during his conflict with Tiridates.

The long-standing alliance between the Saka-Scythians of Sistan and the Arsacid dynasty was not merely a military arrangement but also a crucial component of Parthian economic strategy. Although nominally subject to the Kushan Empire, these Scythian chieftains retained significant latitude in their dealings with the Parthians, in part because they served as vital intermediaries in the overland trade routes linking Iran with India and Central Asia. The urban centers of Sakastan and Bactria became major nodes in a commercial network extending from Kerman and Pars in southern Iran to the Gulf littorals of ancient Arabia and Mesopotamia.

Luxury goods—such as Chinese silks, Indian spices, and gemstones—were transported through this vast network, which extended from the Pamir Plateau to the Persian Gulf, and from there to the Arabian Sea, the Red Sea port of Aqaba, Petra, and the eastern Mediterranean. Thus, the geopolitical and economic cooperation between the Saka and the Arsacids was mutually beneficial, underpinning regional stability and Parthian diplomatic leverage.

The Restoration of Phraates IV and Diplomatic Engagement with Rome

According to the Roman epitomator Justin, Phraates IV, after his triumph over Mark Antony, became increasingly despotic, provoking discontent among the Parthian aristocracy. This internal disaffection culminated in a revolt led by Tiridates, who, after seizing the capital, compelled Phraates to flee. The deposed king wandered for some time through neighboring territories before seeking military aid from the loyal Saka of Sistan. With their support, Phraates returned at the head of a formidable army and reclaimed the throne.

Justin recounts that during Phraates’s exile, Tiridates had been proclaimed king by the Parthians. However, upon learning of the advancing Scythian forces, he fled with a group of supporters to the Roman court. There, he sought the protection of Caesar Augustus, who was then engaged in military operations in Hispania. Crucially, Tiridates had taken with him the young son of Phraates—possibly as a political hostage to enhance his claim to legitimacy in Roman eyes.

Phraates responded swiftly, dispatching envoys to Augustus to demand the return of both his rebellious “servant” and his son.  According to Justin, Tiridates had appealed to Augustus for assistance in regaining the throne, offering to place Parthia under Roman suzerainty in exchange for military support. Augustus, however, remained mindful of Rome's disastrous defeats in Parthia—Crassus's annihilation at Carrhae and Antony's humiliating failed campaigns—and opted for a cautious diplomatic approach. He refused to restore Tiridates or commit Roman forces to what he viewed as a lost cause, unwilling to risk another costly military confrontation with Parthia. Yet Augustus also sought to avoid completely alienating Parthia. To appease Phraates without appearing weak, he returned the king's son as a gesture of goodwill, while simultaneously granting Tiridates a Roman pension to maintain him in comfortable exile—a solution that kept the pretender available as a potential future asset while avoiding immediate military entanglement.

 Later, as Augustus concluded his campaigns in Spain and prepared to assume command in the East, Phraates grew apprehensive about potential Roman aggression. In a diplomatic gesture designed to neutralize hostilities, he released surviving Roman prisoners from the campaigns of Crassus and Antony, and returned the legionary standards—signa militaria—captured during those disastrous encounters. He also sent his own sons and grandsons to Augustus, ostensibly as an act of goodwill in accordance with Roman diplomatic customs. However, this arrangement served dual purposes: it demonstrated Phraates's peaceful intentions while ensuring his heirs would be protected at the Roman court should he face another internal rebellion like Tiridates's uprising, as foreign-educated princes living under imperial protection would be less vulnerable to domestic conspiracies and court intrigue.

Yet, Roman historians such as Cassius Dio offer a more nuanced version of events. Dio notes that Augustus, after Antony's defeat and death, deliberately maintained neutrality in the Parthian civil strife, waiting for internal dynamics to unfold. Once Phraates had reasserted control and sent an embassy, Augustus began a conciliatory dialogue. He allowed Tiridates to remain in Roman territory without offering military support and accepted the young son of Phraates as a token of renewed diplomatic relations.

The widespread Roman narrative—that Augustus recovered the standards through strength and honor—has been roundly critiqued by modern historians. The evidence strongly suggests that the restitution of the standards was part of a calculated diplomatic exchange rather than the result of Roman coercion. The Parthians had no compelling reason to fear Augustus militarily, but they understood the symbolic importance of the standards to Roman prestige. By returning them, Phraates removed a key pretext for renewed Roman aggression.

Augustus, ever skilled in the optics of imperial propaganda, immortalized the return of the standards as a signal triumph. In Res Gestae Divi Augusti §29, he proclaimed:

"I compelled the Parthians to return the spoils and standards of three Roman legions and to seek the friendship of the Roman people."

Roman poets and historians largely omitted any mention of diplomatic concessions. Instead, they portrayed the episode as a monumental diplomatic victory, akin to a bloodless conquest. A celebratory coin was minted, depicting a submissive Parthian returning the standards to a dignified Roman figure—an artistic fiction rather than historical reality. Augustus also erected the Ara Pacis and the Monumentum Ancyranum to celebrate this achievement, framing it alongside his military successes in Spain, Gaul, and Germania.

There is some confusion in the sources between the son taken hostage by Tiridates and another son of Phraates, who was later sent voluntarily to Rome—possibly at the behest of his Roman mother, Musa (also known as Thea Musa or Thermusa). The merging of these two episodes has led to historiographical ambiguity. What remains clear, however, is that Augustus skillfully transformed a strategic diplomatic exchange into an enduring symbol of Roman superiority—one that continues to be misrepresented in the literary and visual culture of the early Principate.

Rising Unrest in Armenia and the Downfall of Phraates IV

In 20 BC, the death of King Artaxias II of Armenia created a political vacuum that reverberated across the region. At the time, Caesar Augustus was in Syria and promptly dispatched his stepson, Tiberius, to secure Roman interests in Armenia by nominating a compliant successor. Tiberius, calculating the regional balance, proposed the accession of Artaxias’ brother, Tigranes III. Though nominally acquiescent, King Phraates IV of Parthia covertly maintained ties with Armenian factions opposed to Roman domination and likely supported a long-term strategy to reintegrate Armenia into the Iranian imperial orbit. Since the time of Mithradates II, Armenian kings had often hailed from the Arsacid house, and Parthia regarded Armenia as a member of its confederation of vassal kingdoms.

In 10 BC, upon the death of Tigranes III, the Armenian nobility—backed by Phraates IV and without Roman consultation—elected Tigranes IV, the late king’s son, as monarch. Tigranes IV took his sister Erato as queen in a dynastic union rooted in Iranian royal customs. Roman historians, with their usual orientalist prejudice, often highlighted such unions as examples of Parthian “barbarity,” emphasizing incestuous relationships to contrast them with Roman moral sensibilities. However, these critiques often misunderstood the cultural context. While Zoroastrianism—later codified under the Sasanian Empire—permitted close-kin marriages as part of its doctrinal structure, Armenia at this time followed pre-Zoroastrian Mithraic traditions. These Mithraic beliefs did not encourage such unions, and in fact, Armenian elites later resisted Sasanian attempts to impose Zoroastrian orthodoxy on their religious practices. Thus, if Tigranes IV and Erato were indeed half-siblings, the political context and dynastic legitimacy likely outweighed any prevailing religious norms.

Both Tigranes IV and Erato were openly anti-Roman, and Phraates IV, elated by this turn of events, saw their elevation as a chance to assert Parthian influence over the strategic kingdom.

Augustus, however, could not tolerate the loss of Armenia to the Parthian sphere. In 5 BC, he instigated a Roman-backed coup that deposed Tigranes IV and compelled Queen Erato to abdicate. In response, Armenian nationalists appealed directly to Phraates IV for military assistance.

The Arrival of Thea Musa and the Rise of Phraataces

Isidore of Charax recounts that when the rebellion of Tiridates temporarily deposed Phraates IV, he slaughtered members of his own court—including women and children—to prevent them from falling into enemy hands. After regaining power with Scythian support, Augustus, ever the master of subterfuge, sought to pacify Phraates IV and forestall renewed aggression. In a calculated move, he sent a beautiful and intelligent Italian slave-girl, Thea Musa (identified by Josephus as Thermusa), to the Parthian court. Phraates IV soon fell under her spell, took her as consort, and named their son, Phraataces (Phraates V), as heir.

Musa, evidently acting in Rome’s interest, proved a cunning political agent. As Josephus relates, she persuaded Phraates IV to send his four sons from prior marriages—Seraspadanes, Rhodaspes, Bonones, and another Phraates—along with their wives and children, to Rome under the pretense of diplomatic goodwill. Roman sources praised this as a token of Parthian submission, though Persian traditions suggest it was part of a larger ploy orchestrated by Musa to remove rivals to her son’s claim.

While Augustus welcomed the hostages and paraded them as symbols of Rome’s preeminence, Persian chroniclers viewed the affair with suspicion. Strabo confirms that Phraates sent his sons not out of fear but to ensure Rome's friendship. The gesture also served Augustus’s larger narrative of diplomatic victory without bloodshed.

The Poisoning of Phraates IV and Musa’s Co-Regency

By 2 BC, Thea Musa, with the cooperation of her now-adult son Phraataces, poisoned and assassinated Phraates IV. Together, they assumed joint rule, with Musa styling herself queen and goddess, as evidenced by coins bearing her divine image. This unprecedented female co-regency in Parthian history shocked the nobility and alienated key stakeholders.

Musa’s ambitions were not limited to Parthia. Some historians speculate that she was either a daughter of Julius Caesar and Cleopatra VII or, more plausibly, the daughter of Caesarion, Cleopatra’s son. Her full title, Thea Musa Urania, linked her to the celestial goddess Urania, perhaps merging Roman and Mithraic traditions. An inscription from Mount Selan in Kurdistan—acquired by the British Museum in 1913—lists a wife of Phraates IV as Cleopatra, possibly affirming Musa’s maternal lineage.

Diplomatic Maneuvers and Gaius Caesar’s Armenian Campaign

After the assassination of Phraates IV, Augustus dispatched his grandson, Gaius Caesar, to reassert Roman dominance in Armenia. Phraataces, now styling himself King of Kings, sent a diplomatic message to Augustus, claiming rightful rule and requesting the return of his brothers from Rome. Augustus refused and addressed Phraataces without royal titles, denouncing his “illegitimate” accession.

Yet behind this rhetorical hostility lay a pragmatic détente. At a meeting on an island in the Euphrates, both sides agreed to terms: Parthia would withdraw its support for Armenia, effectively recognizing Roman hegemony there. Gaius Caesar then led a campaign to suppress the Armenian revolt and installed Ariobarzanes II, a Median noble of Arsacid descent, as Rome’s client king. Though initially rejected by Armenians, Ariobarzanes’ justice won over local support. Gaius, however, was mortally wounded at Artagira and died soon after.

Collapse of the Musa–Phraataces Regime and Restoration of the Arsacids

The Parthian  senate, increasingly disillusioned with Musa and Phraataces—whom they saw as Romanized outsiders— supported and financed a rebellion. Phraataces was killed amid the upheaval, and a new Arsacid prince, Orodes II (Hordates II), was proclaimed king. His reign, however, was short-lived, as he died under suspicious circumstances during a hunting expedition.

Roman and Parthian narratives diverge widely on these events. Josephus portrays the period as one of dynastic betrayal and foreign corruption, while Persian accounts emphasize Musa’s manipulation and Augustus’s orchestration of Parthian instability. The truth likely lies somewhere in between—a complex interplay of dynastic rivalry, imperial ambition, and the enduring fragility of legitimacy in both the Roman and Parthian worlds.

In the final analysis, the Musa–Phraataces episode underscores the extent to which Rome sought to influence Parthian succession through covert diplomacy and personal manipulation. Yet it also reveals the resilience of the Arsacid tradition, which, even amid political chaos, maintained a powerful hold over the collective imagination and loyalty of the Parthian nobility.

The struggle for Armenia—far more than a provincial dispute—served as the fulcrum of Parthian-Roman rivalry, where kings and emperors alike played a dangerous game of chess across the highlands of the Near East.

The Reign of King Vonones I

After the assassination of Phraates IV and his successors, envoys from the Parthians came to Rome to summon Vonones, the eldest of his sons, to the throne. Caesar Augustus considered this an honor and gave the young man a large gift before sending him eastward. The Parthian senate initially received him with joy, as they typically rejoiced at the coronation of a new king. But that joy soon transformed into bitter resentment: "The Parthians were indignant: they had gone to another continent to have a king tainted by the arts of the enemy. And now the crown of the Arsacids was being bestowed upon a prince who had become virtually a Roman provincial. If this protégé of Caesar, who had borne the burden of his cultural servitude for so many years, should rule the Parthians, where was the glory of the men who killed Crassus and drove Antony from Parthia?"

When they observed that Vonones had become alien to the rites of his race, Parthian displeasure intensified dramatically. He rarely appeared in the hunting grounds and showed little fondness for horses—essential markers of Parthian aristocratic culture. When he passed through city streets, he sat upon a litter in the Roman manner rather than riding horseback as Parthian tradition demanded, and he displayed obvious aversion to traditional Parthian feasts. Among other sources of derision were his Greek companions and his disposition to keep even the most mundane household utensils under Roman-style seals. Conversely, he proved accessible to petitioners and demonstrated immense personal kindness—qualities that, while valued differently within respective cultural systems, were interpreted by Parthians as inappropriate departures from traditional royal dignity and proper hierarchical distance.

It is crucial to recognize the Romano-centric bias inherent in Tacitus's account here. The Roman historian presents Vonones's accessibility and kindness as inherently superior virtues "unknown to the Parthians," thereby perpetuating the typical Roman stereotype of Eastern despotism versus Western benevolence. This perspective fundamentally misrepresents Parthian political culture, which maintained its own sophisticated concepts of royal responsibility, justice, and appropriate governance. Parthian kings were expected to embody majesty and maintain ceremonial distance not from cruelty or indifference, but because such behavior reinforced the cosmic order and royal legitimacy within Iranian political Mithraic theology based on their sophisticated concept of love. What Romans interpreted as "kindness" may have appeared to Parthians as dangerous weakness that undermined royal dignity and traditional authority structures. The rejection of Vonones thus reflected not Parthian inability to appreciate virtue, but rather incompatible cultural definitions of appropriate royal behavior.

Tacitus's account makes clear that Vonones, raised in Rome since childhood, had acquired thoroughly Westernized behavior, which proved fundamentally unacceptable to Parthian sensibilities. Consequently, the Parthians revolted against Vonones in 12 CE and elected Artabanus III, who had spent his formative years among the Dahae east of the Caspian Sea. Artabanus possessed authentically Iranian temperament and behavior, serving at that time as king of Atropatene Media before his elevation to supreme power. The critical question remains: why did the Parthian assembly not provide the kingship to Artabanus from the beginning? This strongly suggests that Phraates IV had unequivocally designated Vonones as his chosen successor, and the Parthian nobility initially felt obligated to honor that dying wish.

Tacitus reports that in 8 CE, delegates from the Parthian senate journeyed to Rome specifically to offer the throne to Vonones and request Augustus return him to Persia as king. Augustus was exceedingly pleased with this formal invitation precisely because Vonones had thoroughly adopted Roman character, behavior, and culture during his lengthy Roman sojourn. In his account of this period, Cornelius Tacitus preserves a rare fragment of what appears to be a Parthian historical inscription—possibly the only surviving historiographical text from the Arsacid period. Unfortunately, Tacitus provides no attribution or source reference for this inscription, though it may have derived from a now-lost Parthian chronicle. The significance of this fragmentary text lies in demonstrating that the Arsacids not only maintained pre-Zoroastrian cultural traditions but also possessed rational and critical historiographical practices. Tragically, as subsequent events would prove, these writings vanished during the Sasanian era along with broader pre-Zoroastrian cultural elements, leaving historical writing largely confined to Zoroastrian priestly circles.

The inscription describes events thus: "They summoned Artabanus, who was of Arsacid blood and had spent his youth among the Dahae. Though he was defeated in his first engagement, he regathered his forces and obtained the reins of the kingdom. The defeated Vonones took refuge in Armenia, which was then effectively independent under the competing influences of Persia and Rome—a situation resulting from Antony's duplicitous conduct when he had deceived Artavazad, king of the Armenians, under pretense of friendship, then chained and ultimately executed him. Artavazad's son Artaxerxes, mindful of his father's fate and harboring blood enmity toward Rome, had turned to the mighty Arsacids for protection of himself and his country. When Artaxerxes was subsequently killed by disloyal relatives, Caesar appointed Tigranes to rule the Armenians, and he obtained the kingdom with support from Tiberius Nero's guards. But neither Tigranes nor his sons reigned long, despite their foreign-style unification of marriage and royal power."

Artabanus, commanding Atropatene Median troops, initially attacked Vonones in Parthia proper. However, Vonones's Parthian forces defeated him. Vonones struck commemorative coinage celebrating this victory, inscribed: "King Vonones defeated Artabanus." Artabanus, however, remained undeterred by this setback and, though greatly discouraged, withdrew to Atropatene Media. After consolidating his position, he assembled a larger army and launched a second campaign against Vonones, achieving decisive victory. Vonones fled hastily to Seleucia, while his slowly retreating troops suffered extensive casualties at Median hands during their withdrawal to that city. Thus Artabanus III entered Ctesiphon in triumph and received coronation as King of Kings.

Vonones's Kingdom in Armenia

Vonones fled to Armenia in 12 CE and was appointed king of that land by Augustus. The background was complex: after Artavasdes II's death in 4 CE, his son Artavazd III had reigned for two years in Armenia. Unlike his father, however, Artavazd III proved an unjust ruler, prompting Armenian rebellion and his assassination in 6 CE. Augustus subsequently appointed Tigranes V as Armenian king. Tigranes V's lineage was remarkably cosmopolitan: his father was Alexander, a Jewish prince who ruled the Nabataean Arab kingdom (in modern Jordan), while his grandfather was Herod, King of Judea. After Alexander's execution in 7 BCE, Herod had sent Tigranes's mother—a Cappadocian princess of mixed Armenian-Iranian-Greek ancestry—back to Cappadocia while retaining custody of young Tigranes V.

Tigranes V's childhood was spent at Herod's Jerusalem court. Three years after Herod's death in 4 BCE, Tigranes and his brother joined their mother in Cappadocia, where they abandoned Judaism and embraced their mother's Greek religious practices. In 6 CE, following Artavazd's assassination by Armenian rebels, Tiberius selected Tigranes V as Armenian king and crowned him in the capital of Artaxata. The Armenians, however, rebelled against this Roman imposition and elected their former queen Erato (widow and sister of Tigranes IV) to co-reign with him. This dual monarchy persisted for six years until 12 CE, when Armenians again rebelled and overthrew both Tigranes V and Erato. At precisely this juncture, Vonones, having fled from Artabanus and sought Armenian refuge, was elected king of Armenia by Roman appointment.

Artabanus III, now firmly established as Parthian King of Kings, appealed to Rome and threatened inevitable war if Vonones was not returned to him. Rome, however, was entirely unprepared for conflict with Persia. Three years earlier, following the catastrophic Battle of the Teutoburg Forest with Germanic tribes, Rome had lost three entire legions—a disaster so devastating that, according to Suetonius, Caesar Augustus was observed banging his head against palace walls while shouting: "Quintilius Varus! Give back my legions!" This Germanic disaster had followed a grueling four-year conflict (6-9 CE) with the Batavians (Bellum Batonianum) in Illyria along the Adriatic coast, where native peoples had risen under two commanders both named Bato, forcing Rome to deploy more than half its military strength—eight legions—from the German frontier to the Balkans. Suetonius characterized this Illyrian war as among Rome's most difficult conflicts since the Punic Wars and the struggles with Mithridates of Pontus.

Consequently, Rome, intimidated by Artabanus III's threats, expelled Vonones from Armenia and transferred him to the Roman governor of Syria, Creticus Silanus, where he received a guard and nominal royal title while remaining effectively an honored prisoner. Subsequently, to further appease Artabanus III, Tiberius—now emperor following Augustus's death—relocated Vonones to Cilicia under guard in the city of Pompeiiopolis. There Vonones attempted escape from his gilded captivity, but his plan was discovered, and he was ultimately killed during the ensuing conflict on the banks of the Pyramus River.

Conclusion: The Reigns of Phraates IV and Vonones I

The parallel reigns of Phraates IV (37-2 BCE) and his son Vonones I (8-12 CE in Parthia, 12-18 CE in Armenia) illuminate fundamental tensions within the Arsacid political system and reveal the complex dynamics of Romano-Parthian relations during the early imperial period.

Phraates IV's reign represents a paradoxical synthesis of military success and political vulnerability. His military achievements were substantial: he successfully repelled Mark Antony's invasion of 36 BCE, maintaining Parthian territorial integrity and demonstrating the empire's continued capacity to resist Roman expansion. His diplomatic acumen is equally evident in the negotiated settlement with Augustus, which secured the return of captured Roman standards while establishing a stable eastern frontier. However, his domestic policies proved ultimately destructive. The systematic elimination of potential rivals through fratricide (if proved to be true), while ensuring short-term stability, created a dangerous succession vacuum. More critically, his decision to send multiple sons to Rome as diplomatic hostages fundamentally compromised the cultural authenticity of the Arsacid succession.

Vonones I's tragic reign exposes the cultural fault lines that would eventually fracture Parthian unity, while also revealing the limitations of Roman historical perspectives. His failure stemmed not from personal inadequacy but from an insurmountable cultural disconnect. Raised within Roman cultural frameworks from childhood, Vonones had internalized values fundamentally incompatible with Parthian aristocratic expectations. His preference for Roman administrative practices, his avoidance of traditional hunting and equestrian activities, and his accessibility to common petitioners all violated core Parthian political customs. However, the Parthian rejection of Vonones should not be interpreted through Romano-centric lenses as evidence of cultural inferiority or despotic tendencies. Rather, it reveals a sophisticated civilization with its own coherent political theology and ceremonial requirements, which proved incompatible with imported Hellenistic or Roman governmental models. The Parthian insistence on cultural authenticity demonstrates not backwardness but rather the strength of indigenous Iranian political traditions that had successfully governed a vast multicultural empire for centuries.

The broader implications extend beyond individual reigns to systemic vulnerabilities within Arsacid governance. First, the succession crisis following Phraates IV's death demonstrates the absence of institutionalized succession mechanisms, leaving the empire perpetually vulnerable to civil conflict. Second, the cultural alienation of Roman-educated princes suggests that diplomatic engagement with Rome, while necessary for frontier security, carried unacceptable internal political costs. Third, the rapid collapse of Vonones's authority indicates that Parthian political legitimacy remained fundamentally dependent upon cultural authenticity rather than administrative competence or foreign recognition.

The Romano-Parthian diplomatic relationship during this period reveals mutual recognition of strategic limitations. Rome's acceptance of Artabanus III's demands and willingness to sacrifice Vonones demonstrates realistic assessment of imperial overstretch following disasters in Germany and Illyria. Conversely, Parthian insistence on cultural orthodoxy, even at the cost of potential Roman accommodation, suggests prioritization of internal cohesion over external advantage.

Ultimately, both reigns foreshadow the gradual dissolution of Arsacid power. Phraates IV's military successes could not compensate for the structural weaknesses his succession policies created, while Vonones I's failure demonstrated the impossibility of cultural synthesis between Iranian and Greco-Roman political traditions. The Arsacid Empire's eventual collapse to the Sasanians would stem largely from these unresolved tensions between the demands of international diplomacy and the requirements of domestic legitimacy—tensions that the reigns of Phraates IV and Vonones I first brought into sharp relief.