At the time of the Parthian uprising in 238 B.C., the currency circulating in northern Iran was similar to that of the rest of the Seleucid empire. However, the mints of Bactra and Hecatompylos were already tending to cater for a preference for the drachm in their area, whereas at Ecbatana this denomination was scarcely issued between the reigns of Antiochus I and III, the emphasis being on the tetradrachm instead. The weight standard employed derived from the Attic system so that in the 3rd century B.C. the drachm weighed about 4 grammes. The regular obverse for this Seleucid coinage was the royal head, bound with the diadem and facing right, while a common reverse motif depicted Apollo seated left on the omphalos and holding a bow.

The majority of the earliest Parthian issues now extant come from a hoard unearthed in the Atrak valley west of Bujnūrd. It contained one tetradrachm and about 1500 drachms, the latest non-Parthian specimen being struck for Diodotus of Bactria; accordingly, a possible occasion for the deposition was the eastern expedition of Antiochus III who set out from Ecbatana in 209 B.C. The most worn, and hence the first Parthian group shows on the obverse a beardless head facing right and wearing a diadem-bound bashlyk; the reverse portrays an archer in steppe dress, seated left on a stool and holding a bow (pl. 1 (1)). It is no surprise to find that they follow Hellenistic prototypes relatively closely in fabric and design, but there are some unusual features.