The Battle of the River Arius (Greek: Areios) today known as the Hari, was one of the battles fought by the Seleucid king Antiochos III the Great (Greek: Megas Antiochos) in his wars to re-unify the Seleucid realm.
The once powerful empire had fallen. By the time that Antiochos III had ascended the throne in 223 BC the Seleucid Empire had begun to disintegrate into several different bickering kingdoms with no sense of unity or loyalty to the throne. Antiochos III was determined to change all that. By 220 the worst of the rebellions, that of Media and Persis, had been put down and the corrupt minister Hermeias was executed. Though revolts still plagued the empire Antiochos felt confident enough to challenge Ptolemaic Egyptin 217, but was defeated at the Battle of Raphia. Unable to expand southwards the young king went north into Asia Minor. There he put down the rebellion of his cousin and former general, Achaios, who held out for four years against government forces before falling in 213.
From there Antiochos III kept moving, and while forced to tolerate the existence of the minor kingdoms of Pergamon, Bithynia, andKappadokia, there was nothing keeping him for going east. The Armenian king Xerxes was forced to submit through a show of overwhelming force in 212. Following this Antiochos pulled back, for beyond Armenia lay the nascent Parthian Empire and theKingdom of Baktria, and Antiochos wisely choose to back off to allow him time to prepare for what promised to be a long hard march in hostile territory. The satrapy that the Parthians were then occupying, that of Parthyaia, had broken away from Seleucid control in250 BC, while the king, Antiochos II Theos, was embroiled in a war with the Ptolemies. The rebellious satrap, named Andragoras, was slain and his satrapy conquered many years later in 238 by invading Iranian nomads called the Parni. By 212 the Parni had become the Parthians, but they had not yet completed the transformation. When Antiochos finally marched against them in 209 he had prepared for fighting in the harsh terrain against a highly mobile opponent. Hekatompylos, the current capital of the Parthians, fell in mere months and the king, Arshak (Greek: Arsaces) II, surrendered. Antiochos decided to adopt a feudal-style ruling arrangement in the East, allow Arshak to continue ruling, but only if he acknowledged the higher authority of the Seleucid king. Now Antiochos IIIset out for the true prize of his expedition: rich and mighty Baktria.
The Baktrian campaign had commenced. The satrapy of Baktria had always been a place of immense importance. To the IraniansBaktria was a spiritual center, being the place where they believed the first king, Kayomart, reigned, as well as being the birthplace ofZarathushtra (Greek: Zoroaster) and the Zoroastrian religion. To the Hellenes Baktria was important for its great wealth, being both fertile and rich in metals. Baktria also saddled the crossroads of the world, as trade to and from India and Central Asia flowed through the land. Antiochos had clear reasons for desiring to bring Baktria back into the fold. Baktria had been nominally independent since the270s, but the reigning satrap Diodotos (sometimes known as Theodotos) was not a fool. He continued to pay tribute to the Seleucidthrone even though its authority was basically nonexistent. In 250 he declared independence and created a small empire. By the time that Antiochos III launched his invasion of Baktria the tides of power had changed. The line of Diodotos had failed and was replaced by the former satrap of Sogdiana, a Magnesian named Euthydemos.
When in 209 BC Antiochos crossed into Baktrian territory his opponent reacted quickly. Setting out from the capital of Baktra with 10,000 cavalry, Euthydemos made with all haste to the River Arius, which Antiochos would have to cross in order to reach Baktra. He set camp on the far side of the river and sent out scout patrols to keep watch for the Seleucids. Antiochos meanwhile had, with his usual impetuousness, ranged out far ahead of his main army with only his elite forces and some supporting infantry and mounted regulars. His own scout patrols soon found the Baktrian patrols, though the true size of the Baktrian force remained unknown. Deciding to take advantage of the situation Antiochos ordered the infantry to cross the Arius during the night, while the scouts retired to a nearby town. The following morning when the Baktrian scouts returned they found an unwelcome surprise. The battle had begun.
The Seleucid forces were nearly all elite. Due to his eagerness to get into battle, a trait that Antiochos III was never able to conquer, he had left behind the majority of his army, taking only his elite and some regular troops. The infantry was made up of theArgyraspidai; the elite infantry battalions formed from the best soldiers of the Pezhetairoi, the foot companions. They numbered at 10,000 men near constantly, an attempt by the Seleucids to mimic the Achaemenid Immortals. In addition was the Hypaspistai, the elite assault infantry of the Seleucid army. The rest of the infantry was made up from of levy archers. Their numbers are unknown. The cavalry was held in reserve across the river. Antiochos was personally accompanied by the Hetairoi, the companions and elite shock cavalry of the Seleucid army. They numbered at 2,000 men in 8 squadrons with 1 squadron being chosen as the King’s personal bodyguard. Antiochos also took along a second group of cavalry to support him, made up of the Prodromoi (the medium regulars), and some mounted skirmishers.
The Baktrians, in their haste, only brought their cavalry forces to the battle. Unfortunately not much is known about the Baktrian forces present at this battle. What we do know is that Baktria fielded some of the most feared cavalry of any state influenced by Alexander. Based upon their experiences in the east the Baktrians combined the Hellenic spirit to their Asiatic mounts, creating a crack force. Contact with the nomadic tribes such as the Parni and Saka also contributed to the mix. It appears from period sources thatEuthydemos roughly divided his cavalry between the lance and sword armed Royal Guards and the armored horse archers.
The battle had been joined. The returning Baktrian scouts were caught completely off guard by the sudden appearance of the Seleukidinfantry on their side of the Arius. However before the scouts could break off Antiochos had crossed the river with his Hetairoi and smashed into them head on. The fighting soon dissolved into a wild and messy melee as other scout squadrons joined in. Antiochossoon found himself caught in middle of the Baktrian forces with only a few guards left to protect him. In a feat of bravery praised by historians since that day Antiochos III fought with great skill and valor and eventually managed to hack his way back to his own lines to organize another charge, which broke the Baktrian line. By this time word had reached Euthydemos of the unexpected Seleucidcrossing. Together with the main body of his forces the Baktrian king raced to the Arius. This time it was Antiochos’ turn to be surprised.
He had thought that the scout force he was currently engaging was the main force. The sight of nearly 10,000 of some of the best cavalry in the east was not what he was expecting. Euthydemos joined the battle was his elite cavalry and began to drive theSeleucids back to the Arius. Antiochos soon found himself surrounded a second time, and at one point according to the historianPolybius he suffered a direct blow to the mouth that knocked out several of his teeth and had a horse killed from under him. It was only the strength and discipline of the Argyraspidai and Hypaspistai, which had positioned itself like a hedgehog to drive off theBaktrian cavalry that prevented a rout.
On the far side of the river the remaining Seleucid cavalry under Panaetolos watched what was happening. Left in reserve in case of the unexpected Panaetolos knew that now was the time to act. The Baktrians, who had charged into the battle in loose order, were thrown into confusion by the sudden appearance of the Seleucid Prodromoi and mounted skirmishers in their previously thought secure flank on the river. The confusion allowed Antiochos to reform his shattered Hetairoi into a cohesive force and charged into theBaktrians. Caught between Antiochos, the regular cavalry, and the elite infantry block the Baktrian cavalry finally broke and fled.Antiochos immediately took to pursuit and took many prisoners. Euthydemos, broken and demoralized by the loss of his best cavalry, retreated with what remained of his forces to the nearby city of Zariaspa and from there to Baktra. The battle was over with a decisive victory for Antiochos III.
After the battle much happened. What had been expected to be a small skirmish had turned into a decisive victory. Emboldened by what he considered to be the killing blow to the Baktrians, Antiochos III quickly rejoined the rest of his army and set out to take Baktra.Euthydemos would attempt to impede him several times, only for the Seleucids to find victory again and again. Antiochos eventually reached Baktra in 208, only to find that the city was heavily fortified. It held out for two years before Euthydemos sent a letter toAntiochos, proposing an end to the fighting.
In this letter, preserved in parts by Polybius, Euthydemos pointed out that Antiochos was wrong to wage this war if his aim was to punish a traitor. He pointed out, correctly, that he personally never revolted against Seleucid rule. Instead he had deposed the ones who had revolted (the line of Diodotos) and thus did Antiochos a service. In addition Euthydemos also pointed out that his position allowed him to guard the Hellenic world from the barbarians beyond his borders. Antiochos, who had been looking for an excuse to get out of this war, accepted the terms as correct. He did however force Euthydemos to acknowledge his authority, but allowed him to keep his throne and rule independently in 206. To seal the deal Euthydemos re-supplied the Seleucid army with provisions and gaveAntiochos his elephant corps as a gift. Antiochos in turn decided to seal the deal on his side by offering one of his daughters to the son of Euthydemos, Demetrios, in marriage. The young prince had made a great impression on the king during negotiations, and he wanted to have him for a son-in-law.
Antiochos III then proceeded to journey southwards into India where he met with Sophagasenus, the local client king for the Mauryan Empire. This mission ended well with the gift of additional elephants. Antiochos, well satisfied with his achievements, turned back for home. He arrived in the capital of Seleukeia in time for New Year’s in April, 205. Antiochos would receive his epithet of ‘the Great‘ for his success in the East. However it would not last for long, as all that Antiochos III achieved would be undone by Rome with their great victory over him at Magnesia in 190.