The Parthians have been able to extend their rule to Bactria, Babylonia, Susiana, and Media, and, under Mithridates II (123-87 BCE), Parthian conquests stretch from India to Armenia.

Antiochus, with Palestine secured, now devotes his attention to recovering the Seleucid domains in the east.

He assembles a powerful army, which once more includes men of Persis and Elymais.

The strength in numbers and the wealth of this army make an impression on contemporaries, who report that even the simple soldiers wear shoes cobbled with gold.

With enthusiastic support from the Hellenized cities, …

…Antiochus drives the Parthians from Mesopotamia and Babylonia and …

…invades Media, where, with the arrival of winter, he quarters his troops in several localities.

Parthian ruler Mithridates I had died in 138 BCE; his son and successor rules as Phraates II.

The Parthians, perhaps hopeful of stirring up civil war behind Antiochus, release his brother Demetrius, who has been their prisoner for a decade.

The Seleucid–Parthian wars have brought about a lasting cultural exchange between East and West.

Greek ideas will be remembered in the East long after they have been forgotten about in the West, while Persian and Indian influences in sciences, literature and architecture will be introduced to western powers such as the Romans.

The westward expansion of Parthia during the war will eventually lead to clashes with the Roman Empire.

The Roman–Parthian Wars will embroil these ancient empires until the third century.

Antiochus VII Sidetes continues on to Media.

His campaigns against Parthia have been successful, and it appears as if he might restore the lost glories of the Seleucids, but the local population, exasperated by the undisciplined Syrian soldiery, rises up in revolt in the winter of 130-129.

Early in the year, the Medians make a surprise attack on the Seleucid winter quarters near Ecbatana, slaying Antiochus and taking his son prisoner.

Thanks to the loyalty of the Medians, whose sentiments contrast with those of the Persians, Phraates II of Parthia is the victor.

The Parthians drive back the last Seleucid counterattack in 129 BCE.

The loss of so much territory sends the already enfeebled empire into a decline from which it can never recover.

The Seleucid Empire becomes a rump state that consists of little more than Antioch and the surrounding lands.

The only reason the Seleucid Empire continues to exist is because the Parthians see it as a useful buffer against the expansionist Roman Republic.

When Pompey leads a Roman expedition into Syria, in 63 BCE, he will annex the Seleucid Empire, and the stage will be set for the Roman–Parthian Wars.

Phraates, weakened in his struggle against Antiochus, had called upon the powerful Saka nomads to the north of his frontiers for aid, promising them payment.

The reinforcements having arrived too late to be of use, he sends them back, which provokes them to revolt and pillage the countryside.

The Greek prisoners drafted by Phraates into his army participate in the pillage, and Phraates loses his life fighting them in 128 in a great battle inside and around Media.

His uncle succeeds him as Artabanus I.

The Seleucid kingdom, prevented from retaking the Parthian lands it once controlled, begins to rapidly disintegrate.

The defeat of Antiochus has finally ended Seleucid dominion over the countries east of the Euphrates River, and marks the beginning of small principalities in both the north and south of Mesopotamia.

In Mesene (also called Characene, Persian Meshan), a Seleucid satrap with an Iranian name, Hyspaosines (also called Aspasine, or Spasines, who reigns from 127 BCE to about 121 BCE, refortifies Antiochia, a town originally founded by Alexander the Great near the junction of the Eulaeus (Karun) and Tigris rivers, and calls it Spasinou Charax (“Fort of Spasines”).