Alexander the Great was on his way from Iran to Babylon. It was 324 BC. As he passed through southern Iraq he founded his very last city, just above the confluence of the Karun River with the Tigris. This was a strategic location, sited on commercial routes connecting India, central Iraq, and Syria. Its name was Alexandria-on-the-Tigris.

Coin of Hyspaosines, minted at Charax Spasinou

Alexander died a year later, and his city did not prosper to start with. In the mid-second century BC it had to be rebuilt after a particularly severe flood, and was renamed Antiochia, but it was only after a repeat of these events that it started to thrive. A local potentate, Hyspaosines, carved out independence from a weakened Seleucid empire and rebuilt the city, which then became known as Charax Spasinou after its founder. Hyspaosines and his queen, Thalassia, were the first rulers of the kingdom of Characene (Mesene). Their wealth was built on maritime power and trade, with a fleet controlling the waters of the Gulf.

A few years later the Arsacid Rulers of Parthia took control of Charax Spasinou. The city then became the main entrepôt for the flourishing trade between the large cities of the Arsacid realm and India.

It was not the end of the Parthian Empire in AD 224 that eventually sent Charax Spasinou into decline, but the silting up of the river channel and the loss of navigable access to the Gulf. The city lost its raison d’être, so the population declined and eventually left altogether. The floodwaters returned, and the city disappeared under silt and sand.