Even in the thirteenth century natural economy had not been replaced to any large extent by money economy.  The great majority of transactions between man and man were carried on without the intervention of money payments; and the amount of coin in circulation was consequently small.[1] The question of currency was not therefore one to engage the serious attention of the writers of the time.  Aquinas does not deal with money in the Summa, except incidentally, and his references to the subject in the De Regimine Principum—­which occur in the chapters of that work of which the authorship is disputed—­simply go to the length of approving Aristotle’s opinions on money, and advising the prince to exercise moderation in the exercise of his power of coining sive in mutando sive in diminuendo pondus.[2]

[Footnote 1:  Brants, op. cit., p. 179; Rambaud, op. cit., p. 73.]

[Footnote 2:  De Reg.  Prin., ii. 13.]

As is often the case, the discussion of the rights and duties of the sovereign in connection with the currency only arose when it became necessary for the public to protest against abuses.  Philip the Fair of France made it part of his policy to increase the revenue by tampering with the coinage, a policy which was continued by his successors, until it became an intolerable grievance to his subjects.  In vain did the Pope thunder against Philip;[1] in vain did the greatest poet of the age denounce

                    ’him that doth work
  With his adulterate money on the Seine.’[2]

[Footnote 1:  Le Blant, Traite historique des Monnaies de France, p. 184.]

[Footnote 2:  Dante, Paradiso, xix.]

Matters continued to grow steadily worse until the middle of the fourteenth century.  During the year 1348 there were no less than eleven variations in the value of money in France; in 1349 there were nine, in 1351 eighteen, in 1353 thirteen, and in 1355 eighteen again.  In the course of a single year the value of the silver mark sprang from four to seventeen livres, and fell back again to four.[1] The practice of fixing the price of many necessary commodities must have aggravated the natural evil consequences of such fluctuations.[2]

[Footnote 1:  Wolowski’s Introduction to Oresme’s Tractatus, p. xxvii.]

[Footnote 2:  See Endemann, Studien, vol. ii. p. 34.]

This grievance had the good result of fixing the attention of scholars on the money question.  ‘Under the stress of facts and of necessity,’ says Brants, ’thinkers applied their minds to the details of the theory of money, which was the department of economics which, thanks to events, received the earliest illumination.  Lawyers, bankers, money-changers, doctors of theology, and publicists of every kind, attached a thoroughly justifiable importance to the question of money.  We are no doubt far from knowing all the treatises which saw the light in the fourteenth