Ignis Sacer (‘Holy Fire’) in the Ancient World

The different diseases that afflicted France in the 10th, 11th, 12th, 13th and 16th centuries which were variously called sacred fire, burning disease, hell fire and Saint Anthony's disease owe their origin to the use of rye ergot.

Taken from the 1771 Traité du Siegle ergoté by Read, a French physician at the Faculty of Medicine in Montpellier (‘Mr. Read, Docteur en Médecine de la Faculté de Montpellier’), this statement is a perfect synopsis of eighteenth-century medical thinking regarding cases of ergotism in previous centuries, a perspective that influenced subsequent medical literature and historiographical output. Discovered approximately a century beforehand, the disease caused by the ingestion of ergot became the focus of numerous medical and scientific treatises abounding with theories about its nature. At the same time, it was concluded that all conditions defined as Saint Anthony's disease or fire in medieval sources, or indeed ignis sacer (feu sacré in Read's text) and ‘mal des ardents’ on French soil should be interpreted as cases of ergotism.

These sources now need to be reread in the light of a philologically correct modern interpretation to understand whether it was accurate to link occurrences of Saint Anthony's fire to epidemics featuring ergotism and to establish when the expression was first used in the central period of the Middle Ages.