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 which was basically what was left of the eastern Roman Empire, the currency system was reorganised, but the coinage mostly consisted of copper and gold. A silver miliaresion was developed, usually with a cross on steps obverse and an inscription forming the reverse. Later, the cup-shaped (or 'scyphate') trachy were issued, but the silver content of these rapidly declined towards only a few per cent, finally ending up as a pure copper coin after the Fourth Crusade (13th century). Muhammad established the Constitution of Medina in 622 in the Arabian Peninsula. After the death of Mohammed in 632, the state