Located in southern Mesopotamia where the Tigris and Euphrates river meet the Persian Gulf, Characene thrived as an important port for trade between the West and India. Charax, the capital of Characene, was founded by Alexander the Great. It existed as an independent kingdom with first, Greek Seleucid and then Parthian overlords. On occasion it even sided with the Romans in their wars with the Parthians. The emperor Trajan, visited Charax in AD 116 during his invasion of Parthia, where he saw ships bound for India. The more centralized Sassanian Empire brought its independence to an end in AD 222.