Introduction (A Treatise on the Alteration of Money‪)‬

Lord Acton stated that "the greater part of the political ideas of Milton, Locke, and Rousseau may be found in the ponderous Latin of Jesuits." (1) The Late Scholastic period (approximately 1300-1600 A.D.) generated some of the most detailed moral analyses of social issues ever produced by Christian writers. In particular, the moral theologians working from, and around, the School of Salamanca in Spain offered penetrating insights into economics, politics, and other social concerns. Prominent among the Latin Jesuits was Father Juan de Mariana. Juan de Mariana, S.J., (1536-1624) was one of the most extraordinary persons of his time. (2) He achieved acclaim for his works On Monarchy (De Rege et Regis Institutione) (3) and History of Spain. (4) John Neville Figgis wrote concerning one chapter of Mariana's book on the monarchy: "The course of the argument is singularly instructive, and much of it might have been written by Locke." (5) Mariana's treatise on money, presented here for the first time in English, also should have earned him a reputation as one of the most profound economic thinkers of his period.