ST. (Διομήδης), a physician, saint, and martyr, was horn at Tarsus in Cilicia, of Christian parents. He lived at Tarsus for some time, and practised as a physician, but afterwards removed to Nicaea in Bithynia, where he continued till his death. We are told that he practised with great success, and used to endeavour, whenever he had an opportunity, to convert his patients to Christianity. For his efforts in this cause he was ordered to be brought before the emperor Diocletian, who at that time happened to be at Nicomedeia in Bithynia, but died on his way thither, about the beginning of the fourth century after Christ. A church was built at Constantinople in his honour by Constantine the Great, which was afterwards adorned and beautified by the emperor Basil I. in the ninth century. He is commemorated by the Romish and Greek churches on the 16th of August. (Acta Sanct. ; Bzovius, Nomenclator Sanctoruum Professione Medicorm, Carpzovius, de Medicis ab Ecclesia pro Sanctis habitis ; Menolog. Graecorum.)