Cosmas and Damian miraculously transplant the black leg of the Ethiopian onto the white body of the patient.

During the persecution under Diocletian, Cosmas and Damian were arrested by order of the Prefect of Cilicia, one Lysias who is otherwise unknown, who ordered them under torture to recant. However, according to legend they stayed true to their faith, enduring being hung on a cross, stoned and shot by arrows and finally suffered execution by beheading. Anthimus, Leontius and Euprepius, their younger brothers, who were inseparable from them throughout life, shared in their martyrdom.

Their most famous miraculous exploit was the grafting of a leg from a recently deceased Ethiopian to replace a patient's ulcered leg, and was the subject of many paintings and illuminations.