The coinage of Artaxerxes, and of the other Sassanian monarchs, is based, in part upon Roman, in part upon Parthian, models. The Roman aureus furnishes the type which is reproduced in the Sassanian gold coins, while the silver coins follow the standard long established in Western Asia, first under the Seleucid, and then under the Arsacid princes. This standard is based upon the Attic drachm, which was adopted by Alexander as the basis of his monetary system. The curious occurrence of a completely different standard for gold and silver in Persia during this period is accounted for by the circumstances of the time at which the coinage took its rise. The Arsacidae had employed no gold coins, but had been content with a silver currency; any gold coin that may have been in use among their subjects for purposes of trade during the continuance of their empire must have been foreign money--Roman, Bactrian, or Indian; but the quantity had probably for the most part been very small. But, about ten years before the accession of Artaxerxes there had been a sudden influx into Western Asia of Roman gold, in consequence of the terms of the treaty concluded between Artabanus and Macrinus (A.D. 217), whereby Rome undertook to pay to Parthia an indemnity of above a million and a half of our money. It is probable that the payment was mostly made in aurei. Artaxerxes thus found current in the countries, which he overran and formed into an empire, two coinages--a gold and a silver--coming from different sources and possessing no common measure. It was simpler and easier to retain what existed, and what had sufficiently adjusted itself through the working of commercial needs, than to invent something new; and hence the anomalous character of the New Persian monetary system. The remarkable bas-relief of Artaxerxes described above and figured below in the chapter on the Art of the Sassanians, is accompanied by a bilingual inscription, or perhaps we should say by two bilingual inscriptions, which possess much antiquarian and some historic interest. The longer of the two runs as follows:--“Pathkar zani mazdisn bagi Artahshatr, malkan malka Airan, minuchitri min Ydztan, bari bagi Pap-aki malka;” while the Greek version of it is-- [Illustration: INSCRIPTION, PAGE 278]