settlements which could have sustained large populations and hence a great resource in manpower. Dense population centers in regions like Babylonia were no doubt attractive to the Romans, whose armies could afford to live off the land. Currency Usually made of silver, the Greek drachma coin, including the tetradrachm, was the standard currency used throughout the Parthian Empire. The Arsacids maintained royal mints at the cities of Hecatompylos, Seleucia, and Ecbatana. They most likely operated a mint at Mithridatkert/Nisa as well. From the empire's inception until its collapse, drachmas produced throughout the Parthian period rarely weighed less than 3.5 g or more than 4.2 g. The first Parthian tetradrachms, weighing in principle around 16 g with some variation, appear after Mithridates I conquered Mesopotamia and were minted exclusively at Seleucia. Society and culture Hellenism and the Iranian revival Although Greek culture of the Seleucids was widely adopted by peoples of the Near East during the Hellenistic period, the Parthian era witnessed an Iranian cultural revival in religion, the arts, and even clothing fashions. Conscious of both the Hellenistic and Persian cultural roots of their kingship, the Arsacid rulers styled themselves after the Persian King of Kings and affirmed that they were also philhellenes ("friends of the Greeks"). The word "philhellene" was inscribed on Parthian coins until the reign of Artabanus II. The discontinuation of this phrase signified the revival of Iranian culture in Parthia. Vologases I was the first Arsacid ruler to have the Parthian script and language appear on his minted coins alongside the now almost illegible Greek. However, the use of Greek-alphabet legends on Parthian coins remained until the collapse of the empire. Greek cultural influence did not disappear from the Parthian Empire, however, and there is evidence that the Arsacids enjoyed Greek theatre. When the head of Crassus was brought to Orodes II, he, alongside Armenian king Artavasdes II, were busy watching a performance of The Bacchae by the playwright Euripides (c. 480–406 BC). The producer of the play decided to use Crassus' actual severed head in place of the stage-prop head of Pentheus. On his coins, Arsaces I is depicted in apparel similar to Achaemenid satraps. According to A. Shahbazi, Arsaces "deliberately diverges from Seleucid coins to emphasize his nationalistic and royal aspirations, and he calls himself Kārny/Karny (Greek: Autocrator), a title already borne by Achaemenid supreme generals, such as Cyrus the Younger." In line with