Few problems of medieval credit have received more attention from continental historians than that of financial instruments. The medieval tratta (bill of exchange), its origin and diffusion, has been a special favourite with the student, and we now know more about its legal and diplomatic evolution in the Middle Ages than we do of its fortunes in modern times. But this added knowledge has had surprisingly little influence upon the relevant principles of economic history. In spite of the accumulating information the writers of economic history are still apt to represent the technique of medieval credit, especially in the transactions of the non-Italian merchants, not only as something far less elaborate and perfect than the modern technique (which would probably be true) but as its complete antipode: the embodiment of an entirely different economic principle, part of a different, ‘medieval’ order of things. To the present day the teaching of economic history in England conforms to the traditional notion which Cunningham has epitomised in his binomial formula: c dealing for credit was little developed and dealing in credit was unknown'. By ‘dealing in credit’ Cunningham obviously meant the selling and the buying of credit: its transfer and circulation. ‘Though bills were used for transmission of wealth, there is a striking difference between those times and ours in the absence of commercial credit (except what corresponds to book debts) as a basis of transactions of other kinds.