Parthamaspates was a puppet ruler put on the Parthian throne by Trajan during his invasion of the region. Parthamaspates is the traditional attribution for this type but since 2013 the type was been tentatively re-attributed to Sanatrukes but dated the same.
Denomination: Silver drachm.
Mint: Ekbatana mint mark but probably Ktesphon.
Reference : Sear GIC 5848. Shore-424
Size: 18.0 x 20.1 mm. Weight: 3.85 grams.
Grade: VF, minor stable green deposits on the reverse.
Obverse: Head of Parthamaspates left.
Reverse: Archer seated right on an omphalos, holding a bow, with a partially blundered (as is normal) Greek inscription around. The monogram for Ekbatana below the bow.
Provenance: I purchased this coin from a collector at a Torex Coin show in Toronto in February of 2016.