Because of its great influence on later treatises on economic morality, the present study will offer a systematic exposition of the doctrine of usury that Pedro Olivi (13th Century) develops in his famous De contractibus. Our purpose is to identify the ultimate foundations of a condemnation that may be difficult to understand from contemporary economic assumptions and yet was persistent among scholastic theologians and jurists. We will defend the thesis according to which the condemnation of usury is based on a well-defined utilitarian criterion. According to this criterion, the malice of this practice lies in the fact that, by its nature, it makes it impossible for the lender to generate a profit for the borrower. Therefore, usury would be a practice unable of generating value that contributes to the common good. On the contrary, it would only be apt to generate an exploitative relationship between the lender and the borrower. By the application of this criterion, it will be explained why other practices that externally have the appearance of a loan with interest are considered legitimate, for which one of the most interesting aspects of the Franciscan's text will be exposed, namely, his doctrine on capital.
