We read likewise of Constantine the African, who, about the year 1050, came to Salerno after a long residence in the East, and gave to the medical school of that city the translations he had made from Arab authors. But, notwithstanding these evidences of Eastern culture, it is certain that the actual introduction of pharmacy into the Northern European countries is much more largely due to the Spanish Mohammedans. In the Middle Ages poor Arabs and Jews who had studied medicine in the schools of Cordova and Seville tramped through France and Germany, selling their remedies, and teaching many things to the monks and priests who, in spite of repeated papal edicts forbidding them to sell medicines, did in fact cultivate all branches of the art of healing, including many superstitions. The edicts themselves are evidence that they sold their services to those who could afford to pay for them. The Medical School of Salerno, already mentioned, was the principal link between the later Greek physicians and the teaching institutions which remain with us to this day, as, for instance, the universities of Paris, Naples, Oxford, Padua, Vienna, and others of later fame. The origin of the school of Salerno is unknown, but it was certainly in existence in the ninth century. It was long supposed to have developed from a monastic institution, but it is now generally believed to have been always a secular school. Its historian, Mazza of Naples, 1681, quotes an ancient chronicle which names Rabbi Elinus (a Jew), Pontus (a Greek), Adala (a Saracen), and Salernus (a Roman) as its founders, but there is no evidence of the epoch to which this refers. Although other subjects were taught at Salerno, it became specially noted for its medical school, and in the ninth century it had assumed the title of Civitas Hippocratica. William of Normandy resorted to Salerno prior to his conquest of England, and a dietetic treatise in verse exists dedicated to his son Robert. It has been claimed that the works of Hippocrates and Galen were studied at Salerno from its earliest days, but so far as this was the case it was by the intermediary of Jewish doctors, who themselves derived their knowledge from Arab sources, that these were available. The original texts of the Greek and Latin authors were not in the hands of European scholars till Aldus of Venice began to reproduce them early in the sixteenth century.