A key figure in the history of scholarship on Roman monetary history is Theodor Mommsen. At the risk of caricature, this chapter outlines the key features of relevance. At its heart is the matter of whether the Romans mismanaged their currency to the extent that it caused an economic crisis, and whether they had any monetary policy beyond debasing their silver coinage to overcome fiscal difficulties. Recovering the monetary history of the Roman empire is essentially an exercise in prehistoric archaeology, in that there is plenty of material evidence but almost no helpful documentary data. The study of Roman coinage as money remained very much subsidiary to its study as a source for history and art. Compared to modern times, the Roman empire would appear to have experienced very low inflation. A research project aims to outline the fineness of Roman silver coinage, and at the same time characterize the metal supplied to the mints, whether freshly mined or recycled.