Money is synonymous with modern understanding of markets. Study of Roman coinage systems has a distinguished pedigree and has made major contributions to our understanding of the Roman economy (Duncan-Jones 1994; K. Greene 1986: 48-66; Howgego 1995; Kent 1987; King and Wigg 1996). Although there were times and places where the money supply seriously lagged behind, the most striking feature is the level of monetization and integration achieved (Howgego 1992, 1994). The eventual evolution ofa coinage system fitted to serve small market transactions is one ofthe clearest indicators ofa market economy, though even more striking is evidence to show that non-cash transactions were often accounted in cash terms to create simple credit systems (Rathbone 1991: 318-30). Although ancient banking was relatively local in operation (Andreau 1999, 2000), there are instances of loans being taken out in one sea-port and repaid in another after sale of cargo (D. 45.1.122.1).
The existence of markets in the ancient world - in the sense that they are understood by modern economists - has been much debated (Polanyi et al. 1957; Temin 2001). If abstract markets remain elusive, the evidence for ‘‘institutional markets’’ is more concrete. The development of physical market locations parallels the evolution of the coinage (de Ligt 1993; Frayn 1993). Many Roman markets were periodic ones, held on a regular cycle, originally based on an eight day week, making markets every nine days reckoned inclusively - hence their term, nundinae (de Ligt 1993; Mac-Mullen 1970; B. D. Shaw 1981a). The Roman state maintained strong controls over markets; it was necessary to seek approval from the Roman Senate or emperor to establish a new market (CIL VIII 11,451, 23,246).