We set out a simple four sector macro model of the economy of the Roman Empire during a period of considerable economic prosperity. Our focus is on gold coins as currency and the seignor- age which the government used to fund its activities. We solve numerically for a balanced growth representation of the economy of the empire, a solution that captures the intricacies of money creation, currency expansion and seignorage. We subscribe to the view that the exhaustion of low-cost gold and silver deposits contributed significantly to the ending of the economic prosper- ity enjoyed by Roman Italy and its provinces during the so-called Pax Romana (31 BC to 165 CE) and we attempt to capture sig- nificant shifts in variables during the decline.