The coins issued by Parthian kings bear important information about the Arsacids’ political ideology. They show that in a certain period there existed a posthumous cult of the kings. This practice, taken over from the Seleucids, was reflected as early as in the coins issued by Arsaces II, who founded the cult of his father Arsaces I. A number of later kings were worshipped in the same way. But the practice ceased in the middle of the 1st century BC. Since then the king’s power was authorized in other sacral forms. Purely Hellenistic forms of sacral authorization of power must have ceded to oriental (Achaemenid and nomadic) paradigms in the period of confrontation with Rome.