Chalkous - Phraates II Ecbatana

Phraates II inherited the Parthian throne from his father Mithradates I and almost immediately faced catastrophic pressure from the Seleucid king Antiochus VII Sidetes, who invaded Mesopotamia and temporarily recaptured much of it around 130 BC. The Parthian response was methodical — exhausting Seleucid supply lines through winter quarters — and Antiochus was killed in 129 BC, ending the last serious Seleucid attempt to recover the east.

Phraates II himself died in 127 BC fighting Saka nomads, the very steppe mercenaries he had recruited to help defeat Antiochus. Ecbatana, the old Median capital, served as a key Parthian administrative mint throughout this turbulent stretch.