Provinces of the Roman Empire - Volume II

The only great state with which the Roman empire bordered was the empire of Iran, based upon that nationality which was best known in antiquity, as it is in the present day, under the name of the Persians, consolidated politically by the old Persian royal family of the Achaemenids and its first great-king Cyrus, united religiously by the faith of Ahura Mazda and of Mithra. No one of the ancient peoples of culture solved the problem of national union equally early and with equal completeness...