They were martyred at Cyrrhus, where a famous basilica was built in their honour and whence their cult spread throughout the Christian world. Other notable churches built in their honour were at Constantinople (5th century) and Rome, where a 6th-century example survives near the Forum, with mosaics of the saints inside. Their names are in the Roman Canon of the Mass.
Their late and historically worthless Legend made them twin brothers and doctors who practised their art without asking for fees: extremely numerous cures of healing were claimed at their intercession. They are the patron saints of doctors; their Acts recount their skill in healing both men and animals. These stories appealed to artists, who depicted not only individual portraits but also whole cycles of their Lives. One of the most notable was painted by Fra Angelico, another is in a 15th-century North Italian antiphoner at the Society of Antiquaries, London. This includes their most picturesque medical achievement: the grafting of a new (white) leg on to the (live) body of a cancerous Negro. The cult was given encouragement and patronage by the Medici, a number of whom were called Cosmo, unexpectedly in view of the saints' reputation for disinterestedness about financial gain. Feast: in the West 26 (formerly 27) September, in the East 1 July or 1 November.
AA.SS. Sept. VII (1760), 430–77;H. Delehaye, ‘Les recueils antiques de Miracles des Saints’, Anal. Boll., xliii (1925), 8–18;M. L. David-Danel, Iconographie des saints médecins Côme et Damien (1958);A. Wittmann, Kosmas und Damian (1967).