When in the 1990s I mentioned to Michael Crawford that I was planning a book on ancient money, he advised me to investigate one coinage, and look at one local monetary economy, before embarking on the larger project of money in classical antiquity. I took his advice, studied Ptolemaic coinage and money, and more than ten years later returned to the original plan. I learnt that any presumed ‘nature’ of ancient money is very different if you use different kinds of evidence, and that any single type of evidence provides a limited perspective. From the correspondence of Cicero, and the volumes of coinage calculated to have moved around the Roman empire, the ancient monetary economy strikes us as very advanced and widespread. In contrast, personal letters, tax receipts, bills and bank accounts surviving from Greco-Roman Egypt suggest that there was a huge discrepancy in economic behaviour between those who had a great deal and those who had very little money at their disposal. Greek and Roman authors, moreover, lead us to believe that outside the great cities and their imperial outreach people did not know money, living primitive lives in huts and woods, and bartering their goods in a natural economy. But archaeology tells a different story: coinage was present in remote places and most ‘barbarians’, too, had some form of money.