I was asked to illustrate the effects of the economic leadership of adAvanced nations by an example drawn from English economic history in the Middle Ages. I have accordingly chosen the subject of Italian contribution to the economic development of medieval England. What prompted this choice was not only the contribution that the Italians in fact made but also the contribution that they are reputed to have made. Indeed their reputation for economic leadership interests me as much as their achievement. For if their reputation and their achievement are collated, something more interesting than a mere illustration of economic leadership may emerge. The illustration may well turn into a cautionary example. I hope I shall not appear immodest or perverse if I suggest that the Italian example may help to circumscribe the historical and the logical validity of the entire concept of economic leadership. For the concept that appears to mean something in historical accounts of economic forms is apt to dissolve as soon as we reach out to the fundamental forces and processes of economic growth.