Sasanian Persia, which succeeded the Parthians, was one of the great powers of late antiquity and the most significant power in the Near East, together with the Roman Empire. This book undertakes a thorough investigation of the diverse range of written, numismatic, and archaeological sources in order to reassess Sasanian political ideology and its sources and influences in the ideologies of the Achaemenid Persian Empire, Babylonian scholarship and prophecy, and Hellenistic Greek thought. It sheds fresh light on the political complexities of early Arsacid and Sasanian history, especially the situation in Babylon and Elymais, and on the Roman propaganda which penetrated, shaped, and determined Roman attitudes towards Sasanian Persia.