Another of the distinguished Salernian physicians of the thirteenth century, one highly esteemed by Frederick II, was John of Procida, who also was active in producing--if not the real author of--the massacre of the Sicilian Vespers, A.D. 1282. In a dispute concerning the question of the two Sicilies he embraced the cause of Prince Manfred, for which he was banished by Charles of Anjou, and took refuge at the court of Peter III, of Arragon, by whom he was created a baron; and he was influential in persuading the latter to assert his claim to the throne of Sicily. By various intrigues at different courts he succeeded in organizing an alliance, which betrayed its existence in this massacre, and finally resulted in the overthrow of the French in Sicily and the transfer of the island to the crown of Spain. He was author of at least two treatises devoted to medicine and philosophy. Other writers of the School of Salernum were: a learned Jew of Agrigentum known as "Farragus," Matthew Sylvaticus, Graphæus, and Cappola. About the middle of the fifteenth century flourished Saladino, famous as an authority on materia medica. It is of no small interest that now, for the first time in history, women began to figure somewhat prominently as writers, practitioners, and even teachers of medicine. About the middle of the eleventh century appeared a work, entitled _De Midierium Passionibus_, attributed to the before-mentioned Trotula, wife of John Platearius, which has descended even to these days. There is nothing in the work to indicate the name or sex of the author, who is invariably spoken of in the third person; consequently Trotula's connection therewith has often been disputed. It mentions{080} a certain "_aqua mirabilis_" composed largely of brandy, which spirit is said to have first been employed medicinally by Thaddeus of Florence, who died in 1295; there is also an account of a patient who _wore spectacles!_ The diseases of women and children are also largely dealt with. The work is undoubtedly an anonymous production of the eleventh century, disfigured by additions of a later day, and ascribed to Trotula, perhaps, because of the celebrity that attached to her; at all events, it is the earliest work ascribed to a female physician, and thus possesses special claims to interest. Later we read of Sichelguada, wife of Robert Guiscard and a graduate of Salernum, who endeavored to poison her step-son, Bohemond, in order to secure the succession of her own child. This infamous plot was furthered by some of the Salernian physicians, and thwarted only by the prompt action of Guiscard, who swore he would slay his wife with his own sword should the malady of Bohemond prove fatal.