As (Roman coin) as, the (2), (2), . After the as had been issued as a cast coin for about seventy years, and its weight had been reduced in several stages, a as was introduced (meaning that it weighed one-sixth of a pound). At about the same time a silver coin, the denarius, was also introduced. Earlier Roman silver coins had been struck on the Greek weight standards that facilitated their use in southern Italy and across the Adriatic, but all Roman coins were now on a Roman weight standard. The denarius, or 'tenner', was at first tariffed at ten asses, but in
Silver coin was governed by caliphs, thus named 'the Caliphate'. As the caliphate expanded into Byzantine territories to the Northwest and conquered the Sassanian (Persian) Empire to the Northeast, the question of a caliphal coinage became imminent. The caliphate adapted the Sassanian drachm as their silver coin. Initially, Arabic inscriptions were added to the Sassanian coin type. Later, the type was completely revised, so as to include inscriptions and ornaments only. (Depictions of human beings is prohibited according to Sunni Islam). These coins are known in Arabic as "dirhem"s. The dirhems of the caliphate gained wide acceptance. They are consequently found along