Large scale excavations at the ancient urban sites of Pella and Jarash (Gerasa) in Jordan have produced a statistically viable body of data on coin supply and circulation in Byzantine and early Islamic Palestine and Arabia. A comparison of the copper coins (folles and fractions) recovered at these sites reveals consistent trends, notably a major increase in supply during the reigns of Justin I and especially Justin II. After Justin II (d. 578) there is a marked decline in the supply and circulation of copper coins, even taking into account ß uctuating production levels and quality of folles in the later sixth and seventh centuries. The presence of a greater number of mints suggests no major consignments but only the local circulation of coins. A minor improvement in coinage levels at Pella in the late sixth to early seventh century may re ß ect the growing local strategic importance of the town. Support for this explanation can be seen in the expansion of Pella's Byzantine fort and, soon after, the important battle between the Islamic and Byzantine armies in 635.