The two treatises in this volume provide insight into the banking industry of the early modern era—and the church’s surrounding debates—from the perspective of one of the most significant theologians of the period. In the first treatise, Thomas Cajetan carefully argues for a use of bills of exchange on the money market (real exchange) that does not run afoul of the church’s condemnation of usury. In the second treatise, Cajetan handles several questions on the nature of usury and outlines the obligations of those who are involved in certain lending.
From the introduction by Raymond de Roover:
"It goes without saying that medieval and Renaissance bankers could not afford to lend money gratuitously and that interest was charged surreptitiously by being concealed in the rate of exchange, but the theologians, including [Thomas] Cajetan, were unable to accept this fact without being forced to condemn all banking as usurious and to brand it as a sinful profession, like pawnbroking, histrionics, or prostitution. This was the ticklish problem with which Cajetan came to grips.
Although he was in sympathy with humanism, he approached the issue in scholastic fashion and tried to determine which exchange transactions were licit and which were illicit. In his tract, he starts out by dividing exchange transactions into three categories: those that were clearly licit, those that were clearly illicit, and those that were doubtful."