The Parni were an eastern Iranian tribe, who practised Iranian polytheism. By the middle of the 3rd-century BC, however, they had been assimilated into the local Parthian culture; they adopted Parthian, a north-western Iranian language, and became adherents of the Zoroastrianism religion, even giving themselves Zoroastrian names, such as Arsaces' father, Phriapites, whose name was derived from Avestan "*Friya pitā" ("father-lover"). Arsaces himself was probably born and raised in Parthia, speaking the Parthian language. According to the French historian Jérôme Gaslain, Arsaces could have arguably spent much of his life in the Seleucid lands, and may even have belonged to the local elite of Parthia.