sources on which to draw, we have the contemporary cuneiform tablets. These, though they are but imperfectly and incompletely published, provide us with occasional glimpses of the political scene from the eastern side. Documents in Pahlavi, the official language of the Parthians, are so scarce as to be negligible. The extensive and well published Parthian coinage is the basis on which any chronology of the rulers must rest.
For the eastern frontier of the empire the Chinese sources provide us with accurate and, for certain periods, fairly complete information. On the Indian frontier we must again depend upon coins and inscriptions, the uncertain dating of which makes their use peculiarly difficult.
An extended criticism of the classical sources is both impossible and unnecessary here. A good brief statement on the general value of the more important writers and their sources may be found in the Cambridge Ancient History, Volumes IX–XI, together with additional bibliography of more detailed criticisms. The brief remarks that follow will be confined to the value and problems of the sources only in so far as they relate to Parthian history.
By far the most difficult period is that prior to the Parthian invasion of Mesopotamia in 141 b.c., for which the bulk of the information is far from contem porary, widely scattered, and small in quantity. We know that numbers of Parthians were in Syria as well
