The Parthians, on the other hand, began at any rate with a treatment of the Persian religion which was respectful and gratifying.

Though perhaps at no time very sincere Zoroastrians, they had conformed to the State religion under the Achaemenian kings; and when the period came that they had themselves to establish a system of government, they gave to the Magian hierarchy a distinct and important place in their governmental machinery.

The council, which advised the monarch, and which helped to elect and (if need were) depose him, was composed of two elements---the _Sophi_, or wise men, who were civilians; and the _Magi_, or priests of the Zoroastrian religion.

The Magi had thus an important political status in Parthia, during the early period of the Empire; but they seem gradually to have declined in favor, and ultimately to have fallen into disrepute.
The Zoroastrian creed was, little by little, superseded among the Parthians by a complex idolatry, which, beginning with an image-worship of the Sun and Moon, proceeded to an association with those deities of the deceased kings of the nation, and finally added to both a worship of ancestral idols, which formed the most cherished possession of each family, and practically monopolized the religious sentiment.

All the old Zoroastrian practices were by degrees laid aside.