How an Ancient Greek King Invaded Asia to Reclaim his Ancestors’ Empire | History Hit

How an Ancient Greek King Invaded Asia to Reclaim his Ancestors’ Empire

Coin depicting the Greco-Bactrian king Eucratides I as a warrior holding a spear.
Image Credit: Public Domain

The story of the Greeks who ruled in Asia is one of the most fascinating in antiquity. Situated on the edge of the known world, our knowledge of the Greco-Bactrian kingdom is shrouded in mystery. Yet in 208 BC, it fought for its very existence against one of the greatest warlords of the ancient world.

Ascending the throne in 223 BC, Antiochus inherited a Seleucid empire that had fallen into a downward spiral. Bactria, Parthia and large swathes of Syria had been lost by his predecessors. Antiochus aimed to stop the rot and restore uncontested Seleucid supremacy in Asia.  It would be no easy task. To achieve this goal he would have to re-unite lands stretching from the borders of India in the East to Macedonia in the West under his rule. Yet Antiochus remained undeterred.

By 210 BC, Antiochus had had mixed success. Although he initially faced great challenges – both against the pretender Molon and then against Ptolemy IV at Raphia in 217 BC – the young Seleucid had quickly recovered, recapturing large amounts of Asia Minor.

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Looking east

Antiochus turned his gaze away from the eastern Mediterranean and towards the east. Antiochus sought to reassert Seleucid supremacy as far as the borders of India. Antiochus gathered a great Seleucid army for this expedition. The ancient source Justin claims it was 100,000 men strong, though this is almost certainly an exaggeration.

Among its ranks was a formidable cavalry body of at least 6,000 men, as well as at least 15,000 heavy infantrymen. They were the nucleus of Antiochus’ army, trained to form the Macedonian phalanx. Among these footmen was Antiochus’ crack unit, the Silver Shields. They were a 10,000 strong division named after Alexander’s own famous infantrymen. 10,000 peltasts, 2,000 Cretan archers and many mercenaries also filled the ranks.

In early 210 BC, Antiochus set off east. Within a year of reaching Parthia’s lands in 209 BC, resistance there had crumbled. Hyrkania was re-captured, as were the cities of Tambrax and Syrinx in southern Parthia. The new Parthian king, Arsaces II, submitted to Antiochus. Parthia belonged to Antiochus. Bactria was next.

Euthydemus acts

The Bactrian monarch Euthydemus, however, gathered a grand army and marched west to confront the Seleucid King. The Bactrian army was undoubtedly powerful. Not only did his infantry nucleus likely consist of Greek colonists trained in the Macedonian manner, but it would have been supported by expert Bactrian light infantry – men skilled at fighting in rough terrain.

That was not all. Among his force Euthydemus had many exotic beasts: terrifying war elephants from India as well as a substantial number of Bactrian camels in his supply train. Alongside all this, Euthydemus had another force more precious than the rest: his 10,000 Bactrian cavalry. Ever since the days of the Persian Empire, Bactria had been famed for its horsemen.

Some undoubtedly fought as light cavalry equipped with bows and javelins. Yet Euthydemus’ most powerful cavalry were his Bactrian cataphracts – heavily armoured horsemen who’s sheer weight could crush almost any opponent. Elite units of Hellenic companion cavalry likely also served alongside. Altogether it was among the most powerful cavalry forces in the known world.

Defending the Arius

Upon hearing that Antiochus’ force was closing in on the Arius River, Euthydemus sent his 10,000 expert cavalry ahead. Their orders were simple: prevent Antiochus’ force from crossing long enough for Euthydemus and his main army to arrive. For Euthydemus, the Arius would be where he would make his stand.

Yet Antiochus would not play Euthydemus’ game. When he was three days march away from the river, reports reached him that Euthydemus’ cavalry were guarding the Arius’ far bank. Without delay, he marched his army towards the river. For three days the Seleucid army marched at a steady pace, slowly approaching the Arius and the enemy. Yet when his army was within a day’s march of the river, Antiochus initiated a brilliant plan.


Antiochus’ reports had revealed much about the Bactrian cavalry awaiting him and they had revealed a flaw in the defence. His scouts had discovered that the Bactrian cavalry were not constantly stationed on the Arius river. The Greek-Roman historian Polybius reports that “he was informed that the cavalry of the enemy kept guard by day on the bank of the river, but at night retired to a city more than twenty stades off.”

That night, as the Bactrian cavalry returned to their cosy night-quarters, Antiochus therefore made his move. Ordering the rest of his army to continue the march the next morning, the Seleucid king gathered his cavalry and light infantry – some 15,000 men – and commenced a rapid march towards the river. The move was almost-perfectly executed. As the sun emerged the next morning, Antiochus’ select force had not only reached the Arius, but most of his force had also crossed completely unopposed. The rest of Antiochus’ army was still some way behind, however, and the Bactrians would soon be upon them.

The Bactrians return

They came sooner than expected. As the last part of Antiochus’ force was still crossing, Seleucid hearts fell. Rushing towards them were 10,000 Bactrian cavalry, alarmed by scouts of Antiochus’ manoeuvre. They were determined to send their foe back across the river. What was more, they had a gleaming opportunity to either kill or capture the Seleucid king.

Seeing the Bactrians advancing, Antiochus could not refuse the fight. Though most of his force were still not formed for battle, he gathered his 2,000 strong bodyguard andsounded the charge. If his small, elite force could hold the Bactrians for long enough for the rest of his army to form up, then Antiochus knew victory would be within sight. The strategy had huge risks.

The Battle of the Arius, 208 BC

Antiochus’ guard and the Bactrians quickly clashed. The fighting was fierce and Antiochus’ bodyguard struggled desperately to defend their king. The Bactrians were eager to drive their foe into the river and regain control of the crossing. A breakthrough was made when Antiochus’ guard routed a Bactrian squadron. The Seleucids started to get the upper hand. Yet fresh Bactrian support then charged in to the Seleucid royal guard.

River Arius (Hari River) with the Minaret of Jam, a UNESCO World Heritage Site in Afghanistan.

Image Credit: Public Domain

Very soon the Seleucid guard began to suffer terribly. Most of their horses were killed from under them and many, including Antiochus, were forced to fight on foot. But Antiochus continued to resist, inspiring his troops with his bravery:

…the king had a horse killed under him and lost some of his teeth by a blow on the mouth: and his whole bearing obtained him a reputation for bravery of the highest description.

Polybius 10.49

The heroics Antiochus showed at the Arius would prove one of his finest moments. Yet even with the king’s brave antics, Antiochus’ guard soon began to waver. As the Bactrian noose closed in around the Seleucid necks all looked lost for Antiochus.


Just as the situation was looking most severe the battle was turned on its head. While Antiochus and his guard desperately fended off their Bactrian foes, his remaining cavalry formed up. Their charge was devastating and shattered the Bactrian cavalry. In disarray those that remained retreated to re-join Euthydemus’ army.

Upon seeing his shattered horsemen re-join his army, Euthydemus was aghast: his foe had shattered his elite corps and had already crossed the Arius. He ordered his remaining forces to retreat while Antiochus advanced into Bactria in pursuit. Though Antiochus may have won this battle, the war was far from over.

‘Paradise of the Earth’

Euthydemus retreated to his capital at Bactra. The majority of his army was still intact, and he now planned to withstand Antiochus long enough for the Seleucid king to sue for terms. No place better suited this than Bactra. Described as ‘the Mother of Cities’ and ‘Paradise of the Earth’, Bactra was a powerful city. Its strategic placement both on the banks of the navigable Oxus and along the lucrative silk road meant that trade flourished in this metropolis.

Alongside Ai-Khanoum, it was one of the richest cities in Bactria. Militarily too, we can presume the city of Bactra was formidable. For two years Antiochus attempted to breach the city to no avail. It proved one of the longest sieges in the whole of the 3rd century BC, second only perhaps to the siege of Syracuse. Finally, as both sides grew weary, talks to find a peaceful solution were initiated.

Depiction of Alexander’s siege of Tyre in 332 BC.

Image Credit: Public Domain


Antiochus was happy to engage in talks. His glorious eastern campaign was taking much longer than he had expected and he was  desperate to complete it. He sent an envoy called Teleas to Euthydemus to negotiate terms. Arriving at Euthydemus’ court, Teleas put forward Antiochus’ demands. We do not know what they were, but it seems probable from Euthydemus’ response that Antiochus deemed Euthydemus a usurper and demanded Bactria return to its rightful place as part of the Seleucid Empire.

But Euthydemus claimed he was no usurper. After all, it was he who had overthrown the Diodotids, the family who had revolted from the Seleucids in the first place. During the talks, Euthydemus also raised another point, which arguably had greater strength than the first.

The nomad threat

Living on the far-edge of the known world also had its downsides. To the north of Bactra, and especially beyond the Jaxartes, lay the land of hordes and steppe: the home of the ‘Scythians’ or ‘Sacae.’ Just as Macedonia and Epirus were the shields of Hellenism from barbarism on the Greek mainland, the Greco-Bactrian kingdom had a similar job in eastern Asia.

Bactria had frequently faced incursions from nomadic tribes in the past. The Persians, Alexander, the Seleucids and now the Greco-Bactrians – they had all built forts on the southern bank of the Jaxartes river to fend off this threat. With Euthydemus holed up in Bactra, that threat was rising. Aware that these nomads, attracted by the turmoil, gathered on his northern border, Euthydemus pleaded to Teleas that:

if Antiochus did not retract this demand [Euthydemus giving up his kingship], neither of them would be secure. The great hordes of Nomads were close at hand and were a great danger to both. If they failed to stop them getting into the country, it would certainly be utterly barbarised.

Polybius 11. 34

Euthydemus’ argument was that if Antiochus removed him from power, then Bactria could fall, quickly followed by the all Hellenism in Asia. Whether this was simply meant as a statement of fact or a more sinister, underlying threat by Euthydemus, it proved effective.

A compromise is reached

The two kings reached an agreement. Euthydemus would remain as king of Bactria, but with certain conditions: not only did Antiochus force him to hand over his mighty elephant division, but it is also likely Euthydemus paid some sort of homage to the Seleucid dynast. Euthydemus sent his son to Antiochus’ camp to confirm. This prince achieved more than simply ratifying this peace.

Upon meeting Euthydemus’ son, Antiochus was greatly impressed by the young man’s character. In Antiochus’ eyes, he was a Hellenistic king in the making. He thus offered his daughter in marriage to the Greco-Bactrian prince as well as confirming Euthydemus as king of Bactria. The young prince’s name was Demetrius, a man who would go on to wage one of the most fascinating campaigns of antiquity.

Antiochus ‘Megas’

Departing Bactria, Antiochus would linger in the far east a while longer. Reaching the Hindu Kush, he renewed Seleucid friendship with the local king Sophagasenus before returning west. Overall, his eastern campaign had been a great success. Hyrkania, Parthia, Aria and Bactria – Antiochus had gained success in all. Yet of them all, his success and personal valour at the Arius River stood out above the rest.

Such was Antiochus’ success in Seleucid eyes that he soon acquired a new moniker. No longer was he Antiochus III; now, he was deemed Antiochus Megas, meaning, ‘the Great.’ For the next 15 years Antiochus continued to expand Seleucid territory in the Mediterranean, attempting to reconquer the final parts of Seleucus’ great empire. His successes would not ultimately last. In 192 BC, Antiochus launched a campaign against a  rising foe in the west that ultimately proved his downfall: Rome.

The rise of the Greco-Bactrians

As for Euthydemus and the Greco-Bactrians, following Antiochus’ departure, the kingdom underwent significant expansion. Under both Euthydemus and his son Demetrius, the Greco-Bactrian Empire began to form. Their subjects honoured the Euthydemid dynasty in return:

Heliodotos dedicated this fragrant altar for Hestia, venerable goddess, illustrious amongst all, in the grove of Zeus, with beautiful trees; he made libations and sacrifices so that the greatest of all kings Euthydemus, as well as his son, the glorious, victorious and remarkable Demetrius, be preserved of all pains…

A dedication to Hestia in honour of Euthydemus and Demetrius, discovered in modern-day Tajikistan

From making contact with the Chinese (whom they called the Seres) in the East, to Arachosia and India in the South, the Greco-Bactrian kingdom would become the dominant force in the far-east – with their descendants even managing to campaign as far as the Ganges river.

Tristan Hughes