What If Rome Conquered Persia? | Alternate History
Historically, Rome has come to define what most of us envision when thinking of the ancient west, Greece perhaps following close behind in part thanks to it’s interwoven history with the Romans. Likewise, as with Rome, we often think of China as the great titan of the ancient far east, however, often glossed over are the myriad of kingdoms and empires which lay between the two, even the Great Empires of the Persians falling victim to these circumstances.
For over a century, the near east, including the lands of Anatolia and Persia, had been dominated by the Seleucid Empire, a remnant of Alexander the Great’s expansions, and for a time, the heart of Hellenistic culture. It was seen in it’s day as a prospering New Greece ruled by Greeks with the intent of settling it’s lands with additional Greek immigrants, as well as uniting with it’s ancestral lands in Europe. While the Seleucids came close to achieving this, they eventually succumbed to economic instability, divisions in the East, as well as the growing dominance of the Roman Republic in the West. The lands of the Seleucids would be overtaken by the Iranian Parthian Empire, whilst Rome took hold of Greece, encroached upon Asia minor, and quite soon, found itself border to border with the Parthians. This traditionally marks the beginning of the near 7 century long Roman Persian Wars, although as we can see, Rome’s qualms with the region of Persia itself date back further than this, even if some might argue indirectly.
The Greco-Roman cultural blend, strategic value of the coastal lands in the near east, as well as historic importance of the cities within the region, made the lands of Syria, Mesopotamia, the Levant, and Anatolia highly prized in the eyes of Rome, and some even desired to conquer the whole of Persia for both it’s riches, and to pacify a realm which for centuries spawned repeated threats to the emerging civilizations of the West. Of these men who eyed Persia as a conquest was Julius Caesar himself.
In 57 BC, the Parthian King had been assassinated by his own sons, who themselves would come into conflict for the throne. The eldest son, Mithridates IV, would be forced to flee to Roman Syria, which soon came under the rule of Marcus Licinius Crassus, a member of the First Triumvirate, the three-man alliance between Caesar, Pompey, and Crassus which in essence granted them dictatorial power over the Republic. Crassus’s predecessor had originally arranged to support Mithridates against his brother with the intention of securing peace between Rome and Parthia, however conflicts elsewhere delayed this, and by the time Crassus came to power, Mithridates had been captured and executed by the Parthians. Despite this, the pieces for invasion had already been placed, and Crassus, though now without a claimant to the throne, did still desire to carry out an invasion. Crassus had achieved his status and reputation through wealth accumulation instead of military achievement as Caesar and Pompey had. Despite their alliance, the three existed in a perpetual rivalry, and Crassus refused to be seen as the weakest link; Parthia, then, was to be his great military achievement, and Caesar, seeing the value in a conquered Parthia, encouraged him, this, however, would turn out terribly for the Romans. A legionary force vastly out numbering the Parthians was defeated through swift archer-cavalry combined tactics. Crassus would not survive his attempted invasion, and his death led Caesar and Pompey to compete for dominance.
Caesar would come out on top following the subsequent civil war, and Pompey would be assassinated in Egypt. Caesar once again took up the cause of invading Persia; to avenge the death of Crassus, to seek retribution for believed support of Pompey during the civil war, but perhaps most importantly, the drive which had stood with him the longest, to achieve the same heights that his hero, Alexander the Great had. Preparations were made for the invasion to begin in late March, but just days before he was to leave Rome, he too would be assassinated.
Caesar’s death would spark a new civil war, which saw victory for the Caesar avenging alliance of Mark Antony, Marcus Aemilius Lepidus, and Octavian, later known as Augustus. These three men would form the Second Triumvirate, an alliance just as uneasy as the prior. Their opponents had been supported by the Parthians, whom, after the defeat of their faction, would have made an attempt on further East Roman Territories. Antony, who had taken up control of the Eastern Provinces, would manage to drive them out, although still their presence in the east proved a threat; so much so that Antony would take up Caesar’s unused plan to invade Persia is a rushed effort, raising an army of 100,000 through the support of Cleopatra in Egypt, but again, this fell short as supplies and siege weaponry which had been separated from his main forces, were targeted and destroyed by Parthians.
Several years later would come the campaign of emperor Trajan; it seemed here that Rome finally had the Parthians on the ropes; he’d successfully invaded Mesopotamia, annexed Armenia, a long disputed buffer between Rome and the Parthians, as well as captured the Parthian capitol, unfortunately for Rome, it would not hold this victory for very long. Uprisings erupted across the the near east, demanding Trajan turn back before dealing the killing blow Parthia. He would pass away some time later, and his successor, Hadrian, believing Rome needed to consolidate rather than expand, undid the conquests of his predecessor, and turned Rome’s focus inward.
Parthia eventually collapsed, both in part to it’s wars with Rome, and tremendous internal strife. It would be succeeded by the Sassanids and what was officially referred to as the Empire of the Iranians. Century after century these wars would continue, proving an immeasurable strain on both; one which left the lands of the two empires ripe for conquest when the Islamic Caliphates first arose from Arabia…the Persians would come to be dominated by a new identity, and the East Roman Empire would collapse…but what if that changed? What if in an alternate timeline, the Romans had succeeded in eliminating the Persians as a constant threat and rival, making use of the land’s tremendous riches, and establishing a more permanent foothold in the East?
Recurrently, we see a number of patterns; that the Romans consistently turned out in superior number, and may well have possessed superior technology, however tactic and endurance proved to win the day for the Persian Empires time and time again. Roman forces also often found themselves managing multiple fronts, be it on account of invasions, uprisings, mutinies, etc. Rome, after all, did need to move and direct it’s armies from quite a distance, whilst the Persians maintained a more direct home-field advantage; sending several legions away with a successful general could cause a power struggle, whilst if the emperor were to directly lead the charge, lands back in the west might fall victim to ambitious generals or politicians. It’s sometimes been said that had the Byzantines the time and capabilities of the early empire, or rather, the capital simply been moved closer east, focus could much more easily be directed to Persia without fear of imperial collapse due to leaving the West unattended.
There are several ways to go about this scenario, but we’ll be focusing on two main efforts; those of Julius Caesar on account of his fame and ambitions, and those of Trajan who had come closest to success.
It’s been famously said that Caesar, upon either being confronted with a statue of Alexander the Great, or reading of his conquests, began to cry, realizing that at his age Alexander had achieved so much, whilst he, in all these years, had done nothing worthy of memory. This was supposedly the spark which ignited Caesar’s passion, and set in his mind a goal to conquer all that which Alexander once had.
Caesar was determined to shift his full focus to the east, and as such, wanted to ensure only his most trusted political allies retained power in what he expected to be three years of absence. With an army of over 60,000 men, Caesar’s campaign would begin with a neutralizing of the Dacian Kingdom, a former ally of Pompey which had begun to threaten Roman lands in the Balkans. The Dacian king himself had been assassinated not long after Caesar had, the Kingdom fracturing soon after; this could mean that Caesar’s war in Dacia would be short, and decisively successful. From there, Caesar would stage his invasion of Parthia through Armenia. When the same tactic was carried out by Antony, the Parthians had avoided engagement, and allowed for a speedy advance by the Romans, however, by doing this, the slowest of group, the supply carts and siege weapons, were left isolated, and exposed to attack; Caesar would not be so hasty as to allow these essential parts of his strategy to be picked off. According to some accounts, Caesar had planned, following his conquest of Parthia, to advance North toward Scythia, whom he would also attempt to conquer, circling back West for an invasion of Germania, and finally return home. The likelihood of this greater conquest being achieved, unless there’s more to the plan left unexplained, is pretty low. A conquest of Parthia alone, however, while requiring more that just brute force, certainly is achievable from the position Caesar would be in; capable of sieging cities, and approaching each battle with tact rather than, as we said, mere brute force. So we assume Rome succeeds, and the Parthians are conquered. What comes next?
Caesar may have escaped his assassination, but the dissident forces which would have perpetrated the act still exist within Rome. While those Caesar left in charge may handle any potential situation before it got out of hand, Caesar’s absence during this time could have easily sparked a minor civil war along similar lines to our own world. Despite the pro-Caesar faction having won in our timeline, the fact that a good part of the army would be stuck in the east might turns factors against their favor, then again, in our world, Caesar’s allies maintained strength in the west, while his adversaries fled to the East. Regardless of how the first phase of battles goes, save for the unlikely chance Caesar’s allies are overwhelmed early on, the war would ultimately end in a victory for Caesar upon his return to Rome; if the conflict between the two sides is close, his allies would only need to hold out until Caesar closed in, allowing for a crushing of the enemy faction from two fronts.
As mentioned before, Rome was quite well overstretched, and the acquisition of Parthia would be the most important matter for Caesar to address. As a resolution, Caesar might opt to place his successor, Octavian, in a leadership position just junior to his own in Parthia; not fearing the ambitions of his own appointed successor, while still seeing him as capable enough to rule a realm almost as great as that of Rome proper. No doubt Caesar would have learned the dangers of an alliance the likes of the Triumvirate, and understood that Rome needed to undergo a reform capable of mending the many present divides within the Republic. The additional need for concentrated power to ensure these reforms be made, as well as the recognition of Caesar and his heir's capabilities by the senate would still lead to the creation of the Roman Empire, with either Caesar or Octavian severing as first Emperor.
The Rome of this timeline would have in essence established the Diarchy of two emperors much early out, simply out of need for stronger regional authority throughout the vast lands of what was now Rome. Which the Great threat of the East now pacified, resources are freed up for internal projects and developments, which the two emperors would have taken up with great effort, knowing the Roman public needed a demonstration of just how things were going to change for the better. Roads, monuments, aqueducts, and more are erected in the years following the war, bringing Rome to a level of prosperity never before seen.
It would be during this period that Octavian would come to understand the threat of Barbarian invasion. Having focused Roman expansion internally, Parthia and the East would remain secure throughout his reign there, however would be forced to repel several invasions from the neighboring kingdoms and tribes along Parthia’s borders. Rome, likewise would be forced to contend with the Germans on a regular basis. Once Octavian came to power in the west, succeeding Caesar, Rome’s attention would again shift to securing the savage lands which bordered the Civilized world to ensure the safety of Rome, and perpetuation of the Empire, at least until is succumbed to enemies and forces from within.
From that foundation, let us move on to the hypothetical invasion of Parthia by Trajan, a man whom Rome regarded as it’s best emperor, one whose military prowess had seen the expansion of Rome to it’s greatest height, not to mention his dedication to making Roman life all the better for the Roman people, and seeing to the construction of several architectural projects. Trajan’s motives for the invasion are hotly debated, ranging from cornering the trade market with Arabia and India, to attempts at emulating Alexander’s conquests, much like Caesar. Officially the basis had been an unacceptable deposing of the Armenian king by the Parthians, Armenia at the time being a buffer-state which they shared dominance over, however this may have just been an excuse to act, as interest in an invasion of Parthia by Trajan had been expressed quite some time prior to this.
Trajan succeeded in conquering Armenia and Mesopotamia, captured the Parthian capital, and installed a client king to rule the domain for Rome. A major contributing factor to the ease with which Trajan had come so far was the fact that Parthia had been engaged in a civil war at the time. Unfortunately, these successes would not last long as many of the lands conquered would rise up in revolt, demanding Trajan’s forces fall back, ultimately depleting their resources, and encouraging Trajan to end the campaign. The Roman Client King in Parthia would be overthrown, and Trajan began planning a follow-up invasion, but before he could, he would pass away.
Unlike those who invaded Persia before him, Trajan was an old man, sixty years old by the time conflicts began. Trajan specifically emphasized while terminating the campaign that his age hindered further efforts through the hot desert climate, an environment which was in great part responsible for his demise. A historian of the time even wrote of observing him looking longingly to a ship sailing east, and wishing he was as young as Alexander the Great during his campaign.
Disorganization had impacted the effort from the beginning, however Trajan’s skill, and the weakness of the Parthians during this time allowed him to reach further than his predecessors. If we were to assume the campaign be better coordinated, perhaps Trajan delegating the effort to a trusted and seasoned general, it’s quite possible a conquest could emerge successful. Initial efforts would likely focus on capturing the coastal lands along the Persian gulf, with the Iranian Plateau being held off for a later campaign. The landscape of the Plateau would have given a great strategic advantage to Persian archers, whose numbers would no doubt be significantly higher in the heart of their own territory. Supposedly Trajan’s interests did lie in securing Roman trade in the gulf region, given this option just a bit more weight to it. The eastern lands of Persia were also less impacted by the civil war than the western parts had been, meaning this remnant of the empire could be expected to put up more of a fight. That said, Parthia reduced of this territory, and now vulnerable to major Roman naval attacks from the north and south, might fall not to Rome, but the neighboring Kushan empire, who themselves would see a territorial break up in the following century, one exploited by the later Sassanids of our world, however, with the Gulf coast occupied by Rome, the Sassanids may never emerge as a significant power in this alternate timeline.
The Kushans had faced a notable decline in our world following the break up of the Han empire in China, one of their major trade partners. With the expansionist Sassanids now their only remaining Empire-level neighbor, the Kushan’s time as the bridge between West and East had come to an end; that’s not the case in this alternate timeline thanks to the presence of Rome.
Emperor Trajan would be succeeded by Hadrian, who emphasized the importance of securing Romes borders as they stood, and optimizing governance across it’s wide-stretching lands. What this would mean for Rome’s newly acquired lands in Persia is the creation of client kingdoms instead of direct annexation into the empire, with perhaps the exception of Armenia to finally secure this strategically valuable land. This would be followed by the rule of Antoninus Pius, an emperor whose rule was remarkable for the level of sustained peace throughout the Empire, an minimal military interventions outside the empire; Hadrian's consolidation of Roman order, followed by the prosperity of Antoninus would allow Rome to extract significant wealth from it’s puppeted lands in Persia, providing a rich inheritance for the following reign of Marcus Aurelius. Throughout this period, Rome would have increased contact with the far east thanks to more direct and regular interaction with the Kushan empire, potentially opening the door for Buddhism to spread further into the West, whilst Roman culture and technology took on a more prominent role in Han China. This increased interaction between the west and east, could, however, have the great detrimental effect of magnifying the Antonine Plague, which many speculate to have originated in China.
Marcus Aurelius would be forced to deal not only with the effects of this plague, but also continued incursions by the Germanic tribes; hopefully the additional wealth reserves left over by his predecessors, in addition to the absence of a major enemy in the east would allow him to better tackle these issues, perhaps successfully annexing certain territories north of the Danube, and more permanently pacifying the German tribes…however…
As the reign of the Five Good emperors came to an end, so would Rome’s upward trajectory turn to a decline. In our world, Marcus Aurelius’s son and successor Commodus infamously abandoned the near victorious campaigns started by his father against the Germans, essentially bankrupt the treasury through reckless spending, and much more. Any additional gains acquired in the previous regimes would in most part be lost, the client states of Persia eventually breaking away, Rome falling upon hard economic times, and the Germans about as much a threat as they had been before. The third century had been a hard time for most major empires of the old world, as it would turn out, that is, with the exception of the Sassanids, would exploited the weakness of their neighbors to rapidly expand across the Persian domain. The Sassanids, if they do still emerge in this timeline, are far less of a threat on account of prior Roman management. Long term, this allows for a period of recovery in which Rome is able to more easily defend itself without threat of invasions from the East.
Once Rome recovered, and the Diarchy was established, the lands of Persia would once again come under Roman control, although it’s difficult to say at this point what other powers would have filled the vacuum left in the East. If Rome is able to maintain a level of peace in the region, that is, prevent a new Persian empire of some variety from emerging, this would keep Rome in a stronger position when it would need face off against other major threats, notably the Germans, Huns, Muslims, and later the Mongol Empire. Without the need to fight constant major wars in the east, there’s a better chance for Germania to finally be dealt with in some fashion, and if so, Rome would be able to more efficiently protect itself from direct invasions. Because the forces of Rome and Persia aren’t locked in a constant battle which ultimately leaves them too exhausted to defend themselves, the rise of Islam, if in fact it still comes to be, is confined to the Arabian Peninsula, and never expands into former Roman and Persian lands. The Mongols might prove the greatest challenge, and the one which finally pushes Rome back perhaps as far as Anatolia or the Levant. The Mongols would probably cut Rome off from the East for roughly a century before it began to collapse; it’s difficult to say what state Rome would be in at that time, but given this experience in needing hold Mongol invasion off, the Empire might have come to adopt a defensive long-term strategy, and abandoned the premise of holding Persia; but it could finally say confidently that for a time, it did, and through it was able to spread Roman culture more widely across the far-east, as well as find some new eastern contributions to it’s own land.
