Much has been said about the intolerance of ecclesiastical authorities toward the Jews, and of Church decrees that either absolutely forbade their practice of the medical profession and their devotion to scientific study, or at least made these pursuits much more difficult for them than for others. Of course it has to be conceded, even by those who most insistently urge the existence of formal legislation in the matter, that in spite of these decrees and intolerance and opposition, Jews continued to practise medicine and to be the chosen physicians of kings and even of high ecclesiastical dignitaries, as well indeed of the Popes themselves. This, it is usually declared, must be attributed to the surpassing skill of the Jewish physicians, causing men to overcome their prejudices and override even their own legal regulations. There is no doubt at all about the skill of Jewish physicians at many times during the Middle Ages. There is no doubt also of the sentiment of opposition that often developed between the Christian peoples and the Jews. Any excuse is good enough to justify men, to themselves at least, in putting obstacles in the paths of those who are more successful than they are themselves. Religion often became a cloak for ill-will and persecution. The state of affairs that has been presumed however, according to which laws and decrees were being constantly issued forbidding the practice of medicine to Jews by the ecclesiastical authorities, while at the same time they themselves and those who were nearest to them were employing Jewish physicians, is an absurdity that on the face of it calls for investigation of the conditions and from its very appearance would indicate that the ordinary historical assumption in the matter must be wrong.