A Medical Error of Saints Cosmas and Damian: Reflections on Fallibility and Medical Education From a Medieval Miracle

1/4 https://jkms.orgSaints Cosmas and Damian-twin brothers, Christian martyrs, and among the most venerated medical figures in medieval and Renaissance Europe-were renowned as anargyroi, practitioners who provided medical care free of charge. 1 -5 Over time, they became revered as the patron saints of medicine, gradually displacing the worship of Asclepius, the Greek god of medicine, in the Christian world.6 Their most famous miracle, as recounted in Jacobus de Voragine's The Golden Legend (Legenda Aurea)-one of the most widely read medieval texts that profoundly shaped popular hagiographic narratives 7 -describes a divine transplantation: the saints replaced a verger's gangrenous leg with that of a recently deceased Black man.8 "One of the man's legs had been totally consumed by a cancer.[…] So he sped to the cemetery and brought back the Moor's leg, and the two saints cut off the sick man's leg and inserted the Moor's in its place, carefully anointing the wound.[…] The man woke up, felt no pain, put his hand to his leg, and detected no lesion.[…] Then he came to his senses, bounded joyfully from his bed, and told everyone about what he had seen in his dreams and how he had been healed."This miracle, widely interpreted as a sacred act of healing, has been depicted in religious art for centuries.9,10 Among these visual representations, a particular 13th-century illustration caught our attention due to its striking anatomical inconsistency (Fig. 1A).In the image, the saints are shown amputating the verger's right leg while transplanting a left leg.The mismatch in laterality is unmistakable: the curvature of the medial longitudinal arch and the positioning of the toes clearly reveal whether the leg is left or right, making the discrepancy apparent even to viewers without anatomical expertise.To clarify this discrepancy, we digitally outlined (Fig. 1B) and color-coded the original image (Fig. 1C).Our annotated version highlights the amputated leg in yellow, the transplanted leg in black, and the blanket in blue (Fig. 1C).This confirms that a left leg is being attached, while the amputated right leg lies on the floor.We also created a redrawn version to show correct anatomical alignment, based on the curvature of the medial longitudinal arch and the positioning of the toes (Fig. 1D).