Modern surgery may be said to owe its origin to a school of surgeons, the leaders of whom were educated at Salerno in the early part of the thirteenth century, and who, teaching at various north Italian universities, wrote out their surgical principles and experiences in a series of important contributions to that department of medical science. The fact that the origin of the school was at Salerno, where, as is well known, Arabian influence counted for much and for which Constantine's translations of Arabian works proved such a stimulus a century before, makes most students conclude that this later medieval surgical development is simply a continuation of the Arabian surgery that, as we have seen, developed very interestingly during the earlier Middle Ages. Any such idea, however, is not founded on the realities of the situation, but on an assumption with regard to the extent of Arabian influence. Gurlt in his "History of Surgery" (Vol. I, page 701) completely contradicts this idea, and says with regard to the first of the great Italian writers on surgery, Rogero, that "though Arabian works on surgery had been brought over to Italy by Constantine Africanus a hundred years before Roger's time, these exercised no influence over Italian surgery in the next century, and there is scarcely a trace of the surgical knowledge of the Arabs to be found in Roger's works." It is in the history of medicine particularly that it is possible to trace the true influence of the Arabs on European thought in the later Middle Ages. We have already seen in the chapter on Salerno that Arabian influence did harm to Salernitan medical teaching. The school of Salerno itself had developed simple, dietetic, hygienic, and general remedial measures that included the use of only a comparatively small amount of drugs. Its teachers emphasized nature's curative powers. With Arabian influence came polypharmacy, distrust of nature, and attempts to cure disease rather than help nature. In surgery, which developed very wonderfully in the thirteenth and fourteenth centuries, Salerno must be credited with the incentive that led up to the marvellous development that came. With this, however, Arabian influence has nothing to do. Gurlt, besides calling attention to the fact that the author of the first great text-book on the subject not only did not draw his inspiration from Arab sources, insisted that "instead of any Arabisms being found in his [Roger's] writings many Graecisms occur." The Salernitan school of surgery drank at the fountain-head of Greek surgery. Apart from Greek sources Roger's book rests entirely upon his own experiences, those of his teachers and his colleagues, and the tradition in surgery that had developed at Salerno. This tradition was entirely from the Greek. Roger himself says in one place, "We have resolved to write out deliberately our methods of operation such as they have been derived from our own experience and that of our colleagues and illustrious men."