In 197 BC, the Romans faced their greatest enemy. You won't believe what they did next

When an ambitious Seleucid king marched his vast army into Europe to challenge the Roman Republic for control of the Mediterranean world, it looked set to spark a violent clash of the ancient titans. Instead, as Michael Economou reveals, the cunning Romans deployed another potent weapon: diplomacy

Ancient tomb fresco depicting a row of soldiers standing in a procession, holding spears and round, colourful shields

Published: October 19, 2026 at 3:20 PM

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In the spring of 197 BC, a vast war host rumbled west through the mountains of Asia Minor – the region now known as Anatolia, Turkey. Among its ranks were men assembled from across the known world. Clattering columns of Macedonian pikemen marched alongside auxiliaries from Syria, Palestine, Iran and central Asia, while glittering horsemen in heavy armour rode forward in the shadow of Indian war elephants.

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This colossal, multi-ethnic army was united by its charismatic leader, Antiochus III, king of the Seleucid empire and one of the ancient Mediterranean’s most ambitious rulers. The Seleucids, a Macedonian dynasty descended from one of Alexander the Great’s generals, already held sway over an enormous realm stretching from the east of what’s now Turkey to the edge of India. The aim of Antiochus’s expedition, according to the Roman historian Livy, was to “drag all of the cities of Asia Minor into the structure of [his] empire”, then push across the Hellespont (Dardanelles) into Europe itself.

Classical marble portrait bust of a Roman man with short hair and a headband, isolated against a solid black background

An ancient copy of a marble bust purportedly depicting Seleucid king Antiochus III | Credit: Bridgeman

These territories, which today comprise western Turkey and eastern Greece, encompassed fertile valleys, vibrant commercial hubs and vital axes of communication between Europe and Asia – a tempting prize for a great conqueror. For the Seleucids, it also had symbolic importance. The founder of the dynasty, Seleucus I Nicator, had conquered much of Asia Minor after Alexander’s death but, over recent decades, the empire had been losing ground to other regional powers. Antiochus’s march west was not simply an imperialist grab for valuable territory but an attempt to reclaim lost Seleucid territory and establish himself as the successor to Alexander the Great.

Opposing forces

As Antiochus bore down on the Aegean from the east, however, another power was pushing from the west: the Roman Republic. After decades of costly wars – most consequentially with Carthage under the military leadership of Hannibal, who’d invaded Italy via the Alps with his war elephants – by the end of the third century BC, Rome had emerged as the dominant force in the western Mediterranean. In 200 BC, less than a year after its victory in the Second Punic War, Rome’s battle-hardened legions had crossed the Adriatic and clashed with the armies of Macedon, Alexander the Great’s former homeland.

Ancient Seleucid silver coin reverse depicting an elephant walking right, framed by Greek inscriptions above and below with an anchor symbol at the bottom, set against a plain white background

Antiochus’s army included war elephants, as depicted on a coin of the founder of his dynasty, Seleucus I Nicator | Credit: Alamy

Within three years, Macedon had been defeated and its king, Philip V – once a charismatic, expansionist ruler in the mould of Antiochus III – was reduced to a compliant Roman puppet. The Greek city-states ringing the Aegean basin had mostly been Macedonian client states, and were now liberated from foreign rule and granted independence under Roman protection. As Rome set about enforcing its new order in the region, the stage was set for a titanic clash between the Republic and the approaching Seleucid juggernaut.

Yet the seemingly inevitable military confrontation didn’t transpire – not immediately. For the time being, the conflict was fought not by soldiers and ships but through treaties, embassies and public proclamations aiming to win the allegiance of local powers and sketch out competing territorial claims. This struggle – famously described in the 1950s by historian Ernst Badian as a “cold war” – is not only a fascinating story of ancient superpower rivalry but a revealing case study of the more subtle dimensions of Roman imperialism.

Historical map of the Aegean Sea and Eastern Mediterranean showing territories divided by alliances: red for the Seleucid Alliance, orange for the Roman Alliance, and light green for Neutral States

The battleground between the Seleucid empire and Rome

Rome’s conquest of the Mediterranean is often portrayed simply as a triumph of an unstoppable war machine. But the legions were often preceded by diplomats and administrators who cultivated alliances, gathered information and disseminated propaganda. It was these methods – which might be termed ‘soft power’ – that Rome used first to challenge Antiochus’s advance and cement its influence in the Aegean.

This fascinating story of ancient superpower rivalry reveals more subtle dimensions of Roman imperialism

Imperial expansions

At the turn of the second century BC, the Seleucid empire was the largest power in the eastern Mediterranean. Antiochus III himself had done much to augment the empire’s size and prestige during his 25-year reign. Self-styled as Antiochus the Great, he had spent years dashing across the known world dispatching rivals and seizing new lands. In 200 BC, he struck the Ptolemaic Kingdom, then in the midst of a major uprising, and claimed a sizable chunk of territory encompassing much of the Levant. So, as the Seleucid army marched west in 197 BC, he had good reason to feel confident of another spectacular victory.

At first, Antiochus’s forces advanced virtually unopposed, steamrolling the city-states and petty dynasts of the Anatolian interior as his navy swept across the southern coast and captured vital ports. That summer’s campaign concluded with a final, glorious victory when Antiochus captured the ancient and strategically vital city of Ephesus in south-west Asia Minor. As the army wintered in the city and its hinterland, Antiochus and his generals made plans to strike north in the new year and complete their expedition.

Architectural reconstruction artwork of the Temple of Artemis at Ephesus, featuring tall fluted Ionic columns with painted bases, a blue pediment filled with gold relief figures, and guards on horseback stationed along the steps

The Temple of Artemis at Ephesus, one of the wonders of the ancient world. The city was taken by Antiochus as a stepping-stone for his campaign into Europe | Credit: Bridgeman

Most coastal settlements in Asia Minor waited anxiously for the Seleucid hammer-blow to fall, and were prepared to surrender without a fight. A few brave cities, however, took the bold decision to resist Seleucid domination – most notably the great commercial centres of Smyrna (now İzmir) and Lampsacus on the Dardanelles. Knowing that they had little prospect of survival on their own, they turned to the other great power of the region for support, dispatching embassies to secure Roman guarantees for their independence.

Unfortunately for the Smyrnaean and Lampsacene ambassadors, diplomacy in the Mediterranean in the early second century BC was usually improvised and ad hoc, and it was difficult to discern exactly whom they should petition for Roman support. The circuitous journey of the Lampsacene ambassador, Hegesias, has been preserved in a public inscription erected by the citizens of the city to thank him for his efforts. First, Hegesias sailed to mainland Greece and spoke to Rome’s naval commander in the region, who responded with encouraging but vague assurances of support.

He then ventured to Massilia (modern Marseille) – a prosperous Greek colony that was one of Rome’s closest and most loyal allies – where he successfully petitioned the city assembly to help him contact the Senate. Then, with a group of Massiliote advisors in tow, Hegesias travelled to Rome and received an audience with the Senate, which promised to make provisions for Lampsacus in any agreement it reached with Antiochus. On the way home, he made one final stop in Corinth, where he met with the principal Roman official in Greece, Flamininus, and beseeched him to protect Lampsacus’s welfare.

In 196 BC, partly as a result of these panicked embassies, the Roman Senate decided to make a bold declaration. As Antiochus was pressing north and moving to complete his conquest of Asia Minor, the Senate proclaimed that “all of the Greeks in Asia Minor and Europe should be free and self-governing”. The official purpose of this decree was to formally dismantle Macedonian control over the Aegean, and to establish a new status quo in which the autonomy of the Greek city-states was guaranteed by Rome. In reality, however, it was clearly intended as a challenge to Antiochus III, whose expedition aimed to bring these cities under Seleucid control. This is made clear by the text of the decree, which explicitly mentions several cities that had already been taken by Antiochus the previous year.

Classical Roman relief carving depicting a procession of men and priests dressed in draped togas and laurel wreaths, carrying ceremonial objects

Roman senators on a frieze on the Ara Pacis, a first-century BC altar. In 196 BC, the Senate declared that Greek city-states should be self-governing – even those then under Seleucid control | Credit: Alamy

A roar of cheers

Rome reaffirmed this declaration later that year at the Isthmian games, an important Panhellenic festival held near the city of Corinth. The Greek historian Polybius described how, with “the most distinguished men from almost the whole world” in attendance, Flamininus announced that Rome would withdraw its armies from Greece, leaving the cities “without garrisons and subject to no tribute”. At this, the crowd erupted in ecstasy, letting out “such a mighty roar of cheers… that those who listen to the story now could hardly imagine it” and almost killing Flamininus as they showered him with crowns and ceremonial diadems. For the Greeks, the Roman proclamation felt like the end of a nightmare that had begun when Alexander the Great’s father, Philip II of Macedon, had subjugated them almost 150 years ago.

Classical relief sculpture detail depicting a dramatic battle scene between Greek soldiers wearing helmets with shields and Persian or Amazon warriors in tunics and caps

Alexander the Great’s men clash with enemies in a frieze on the so-called Alexander Sarcophagus. Antiochus aimed to prove himself the successor to his illustrious Macedonian forebear | Credit: Bridgeman

For the Romans, the declaration – and the theatrical way it was presented to the Greeks by Flamininus – was a masterstroke that established them as the protectors of Greece and cast Antiochus as an oppressive tyrant who threatened to extinguish the cities’ newfound freedom. It had also immediately created a network of grateful allies in Greece whose infrastructure, manpower and support were more strategically useful (and cheaper) than a permanent Roman garrison.

European ambitions

Yet even as Rome’s propaganda war began to bear fruit, Antiochus was pressing on with his campaign, seeking to create facts on the ground that would be difficult for Rome to challenge through diplomatic manoeuvring. Striking north from Ephesus, he crossed the Dardanelles and marched into Europe. His first act was to restore the Thracian city of Lysimachia, which had recently been destroyed by Rome’s allies during the war against Macedon, and establish it as his primary base in the region. Rebuilding Lysimachia was a clear declaration to Rome that Antiochus intended to remain in Europe and would not meekly accept the diktats of the Roman Senate.

Rome then sent an embassy to Lysimachia to treat directly with Antiochus in a semi-public diplomatic exchange. The Roman case was simple: Antiochus should withdraw from the cities he had taken – which had been open to conquest only because Rome had defeated Philip V – and stop threatening Roman security by pushing into Europe.

Close-up of an ancient silver coin displaying a profile portrait of a bearded ruler with short curly hair wearing a royal diadem headband, mounted against a textured blue background.

A silver coin bearing the face of Philip V of Macedon. Having been bested by Rome, he joined forces with the Republic in its war against the Seleucid empire | Credit: Topfoto

According to Polybius, Antiochus contended that the territory had been rightful Seleucid soil since Seleucus I conquered it decades earlier. As such, Antiochus was not “taking them [the Greek cities] by exploiting Philip’s difficulties, but retaking them in accordance with his rights”. Antiochus also refused to engage the Romans in a performative contest over who was the true ‘liberator’ of Greece. Though in theory he did not object to autonomy for the cities of Asia Minor, he argued that it was his gift to bestow, not the Romans’. As such, he deftly recast ‘freedom’ not as an absolute right granted by the Romans but a privilege that only he could afford to the cities under his control.

Antiochus’s intransigence left Rome in a diplomatic and strategic bind. To declare war would be both a naked act of aggression and an unwelcome new drain on the Republic’s resources. On the other hand, if Rome did not declare war, it would have little choice but to honour its promise and withdraw its forces from the Aegean, leaving it open to further Seleucid attacks.

In the short term, Rome resolved this dilemma by declaring war on Sparta. The city’s new king, Nabis, had been aggressively reasserting Sparta’s position in southern Greece, and Rome’s allies in the region had been asking Flamininus to intervene for some time. The war provided a convenient pretext for Rome to keep its army in the region for another season of campaigning without breaking the commitments it had made at the Isthmian games. However, it did not resolve the deeper strategic problems posed by Antiochus.

Classical stone statue of Carthaginian general Hannibal Barca in military armour and a draped cape, holding a staff while standing next to an ornate urn against a solid black background

A statue of Hannibal, the Carthaginian general whose offer to ally with Antiochus sparked fear in Rome | Credit: Alamy

Hannibal bites back

In 195 BC, an explosive new factor disrupted the delicate diplomatic balance. Exiled from his native Carthage, Rome’s most feared enemy, Hannibal, had made the long journey across the Mediterranean to the court of Antiochus III, where he offered his services. Though Antiochus received Hannibal with little more than respectful courtesy and gave him no major land commands, the news provoked horror among the Roman people, who feared that Hannibal was poised to harry Italy again with a Seleucid army at his back. Over the following two years, the Romans made military plans to defend Sicily and Italy from a potential invasion (though in hindsight such a scenario was highly unlikely).

While some feared that the return of Hannibal would coerce Rome into maintaining its garrison in Greece, the Senate decided to fulfil its promise and withdraw the legions. That said, Rome continued to make its presence felt in the Aegean by establishing itself as a local mediator and guarantor of civic autonomy.

Both sides of an ancient silver Seleucid coin: the obverse shows a profile bust of a diademed king, and the reverse depicts Apollo seated on an omphalos holding a bow and arrow, surrounded by Greek inscriptions

A Seleucid silver coin bearing the head of Antiochus III (left), whose ambitions to expand his empire faltered in the face of Rome’s wily diplomacy | Credit: Topfoto

These interventions did not respect the boundaries of Antiochus’s empire. For instance, a 194/193 BC inscription from the city of Teos on the Ionian coast, then firmly under Antiochus’s control, notes that the Romans officially granted the city exemption from tribute during this period. The Romans euphemistically described these activities as “making friendships”, but Antiochus understood them as a grave threat: they compromised the monopoly on generosity that underpinned Seleucid royal ideology.

That winter, Antiochus sent envoys to Rome in a last-ditch attempt to reach an accord. The discussions followed the same pattern as before, with the Romans (led by Flamininus) insisting that Antiochus evacuate Europe and confine himself to Asia, and Antiochus claiming that Thrace was historic Seleucid territory that he could not abandon. Flamininus, ever the showman, then took the discussion public, delivering a speech affirming that Rome would use force to keep Antiochus out of Europe if he refused their demands.

By this stage, it was becoming clear that only outright war could break the deadlock. On the way back to Antiochus’s court, the nonplussed Seleucid ambassadors paid a visit to the Aetolian League, an alliance of Greek cities that had been Rome’s allies in the war against Philip V but which had been disappointed by the terms of the subsequent peace settlement. Encouraged by the prospect of Seleucid support, the Aetolians put out diplomatic feelers to neighbours in an effort to build an anti-Roman coalition of Greek states. When this proved mostly unsuccessful, the Aetolians began attacking surrounding cities, bringing them into direct conflict with the nearby Achaean League, loyal allies of Rome.

Ancient relief carving on a marble slab depicting a bearded warrior wearing a crested helmet leaning on a spear that pokes a coiled serpent at the base of a pillar

A Greek soldier portrayed on a first-century BC relief. Men from various Greek city-states fought both with and against Antiochus in his conflict with Rome | Credit: Alamy

The Aetolians lost on most fronts but were able to seize Demetrias, a strategically vital fortress-city in Thessaly, and invited Antiochus to occupy it as his new base in Europe. Recognising that war was now inevitable, Antiochus decided that he could not waste the opportunity, and dispatched his army to Demetrias. For Rome, this further incursion into Europe was impossible to ignore, and legions began swarming back across the Adriatic to meet Antiochus. The ‘cold war’ was over, and the real struggle for the Aegean had begun.

Rome and its coalition of allies outnumbered even Antiochus’s enormous war host, an imbalance that only worsened when Philip V of Macedon entered the war against him. Hoping to negate this disadvantage, in 191 BC Antiochus chose to meet the Romans at Thermopylae, the narrow, highly defensible pass where Leonidas I of Sparta had made his heroic stand against the Persian empire almost 300 years earlier. After resisting several waves of Roman attacks, the Seleucid force was ambushed by a flanking manoeuvre through the surrounding heights. Antiochus’s army disintegrated and he was forced to scurry across the Aegean back to Asia Minor and regather his forces. The Roman legions pursued and ultimately defeated him in a decisive battle near the city of Magnesia.

Antiochus was compelled to sign a humiliating peace agreement, the Treaty of Apamea, which stripped his empire of its territories west of the Taurus Mountains and parcelled them out to Roman allies. Even more ruinously, the treaty forced the empire to pay a crippling annual indemnity to Rome amounting to perhaps 10 per cent of the Seleucids’ revenues. The resulting financial crisis drove the Seleucids to squeeze new revenues from their beleaguered subjects, prompting waves of rebellions and political instability.

Antiochus was killed by an angry mob while looting temples – an astonishingly grubby end

Antiochus himself was killed by an angry mob while looting the temples of Elam in south-west Iran – an astonishingly grubby end. A few decades later, Seleucid attempts to extract money from the city of Jerusalem and its rich temple prompted the uprising known as the Maccabean Revolt – the context for the story of Hanukkah, still commemorated by Jews today.

As the Seleucid empire entered into a death spiral and disintegrated over the following decades, Rome continued to push east. The Republic used the same diplomatic toolkit it had deployed against Antiochus as it spread its influence: guaranteeing the autonomy of its allies, establishing itself as the arbiter of local disputes, and threatening potential rivals with overwhelming punishment. It was by these methods, as much as through military force, that Rome finally established itself as sole master of the Mediterranean world.

Michael Economou is a historian and author

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This article was first published in the November 2026 issue of HistoryExtra Magazine

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