When the Huns invaded western India in the late fifth century, they brought with them silver drachms of the Sasanian emperor Piruz (AD 459-84) of Iran, and a tradition for producing their own imitations of coins of this type. The drachm became the accepted prototype for coinage in the region. Coins, known as dramma, continued being made in western India until the thirteenth century. These imitations of the stylized portrait of Piruz, with a fire altar and attendants on the reverse, gradually evolved into increasingly abstract designs: in this example, the winged crown of the king and the fire altar have been reduced to a series of lines and dots. In Gujarat the drammas became smaller and thicker, but their stable silver content made them highly acceptable as currency in neighbouring regions. Early issues have no inscriptions at all, but were presumably struck by the local rulers of Gujarat.