Current debates on the relationship between cultural history and economic history, as illustrated by the KERDOS colloquium, seem to me to pose three questions above all. I shall begin this article by a succinct presentation of them and shall state, in outline, the replies I am inclined to make. Then, I shall examine several specific situations or institutions of an economic character in the Roman world of the late Republican and Imperial periods. My subject matter will be periodic markets (section II), fairs (section III) and monetary loans (section IV). I have chosen these because in my view they bear closely on the three questions I have just alluded to. Studying them will, I hope, help me to fill out in detail the responses that I shall sketch at the outset.