Early Fathers
Adopt an ethical basis to economic prescriptions. St. Jerome is against the accumulation of wealth. St. Augustine defines the 'honest buyer' paying the 'just price' and condemns wealth, especially where it detracts from worship.

Canonists
The Canonists developed the Canon Law, the law derived from the Canon (accepted body of wisdom). The Canon was established at various Councils held throughout Middle Ages (e.g. Council of Nicea 325, Lateran Council 1179). Canon law was often redefined. A standard text is the Decretum Gratiani circa 1140. The Canonists accepted Aristotle's invective against unnatural money-making and particularly interest, but experienced difficulty due to the reality of growth in trade and wealth. Less inclined against wealth, they defended inequality of wealth as God's will.

Up to the 13th Century, the Church prohibition on usury was adhered to closely. Keynes states that he was "... brought up to believe that the attitude of the mediaeval church to the rate of interest was inherently absurd ... but now I read the discussions as an honest attempt to separate what the classical theory has inextricably confused together, namely the rate of interest and the marginal efficiency of capital ... the disquisitions of the schoolmen were directed towards the elucidation of a formula which could allow the schedule of the marginal efficiency of capital to be high, while using rule and custom and the moral law to keep down the rate of interest" (from J. M. Keynes, Theory of Interest Money and Employment cited by A. I. Qureshi, op. cit.).

St. Thomas Acquinas
The manner of using wealth now became important. Wealth itself no longer remained innately evil. Property rights were defended but responsibility enjoined. Thus charity was enjoined so long as it does not cause hardship to the giver. The ultimate good was the Hereafter, and in the meantime imperfections of life remained to be dealt with and regulated according to religion.

Reformists
Luther and Zwingle agreed to the charging of interest amid a gradual weakening of the Church's opposition to interest after the Reformation. 'Usury' came to be defined as an (illegal) high rate of return on money loaned, whereas 'interest' was a (legal) low rate of return on money loaned. (During the 13th Century, interest was termed 'interesse', this being a charge for the late repayment of a loan). The cut off between interest and usury was defined by law, for example during the reign of Henry VIII the maximum rate of interest was set at 10% and anything greater than this was seen as usury. Calvin argued in favour of charging interest.