ἄρσακες
Could not find Ἀρσάκειον in Logeion dictionaries.
Ἀρσάκειον proper-name adjective neuter nominative singular, proper-name adjective neuter accusative singular, proper-name adjective masculine accusative singular of Ἀρσάκειος
ἄρσακες· οἱ βασιλεῖς Περσῶν, Hsch.