Drachm

Mithradates I transformed the Parthian state from a minor breakaway satrapy into a territorial empire rivaling Rome, seizing Media and then Babylonia from the Seleucids between roughly 148 and 141 BC. The coinage shifts across his reign to reflect this — early issues imitating Seleucid conventions, later ones asserting a distinctly Arsacid identity as the mint network expanded westward into freshly conquered territory.

Sellwood 10.1 falls within the transitional phase of that expansion. The fabric tends toward broad and thin, a Seleucid inheritance the Parthian mints never fully abandoned.