Herodotus' account of the mad acts of the Persian king Cambyses II contains one of the two extant pre-Hippocratic Greek references to epilepsy. This reference helps to illuminate Greek thinking about epilepsy, and disease more generally, in the time immediately preceding the publication of the Hippocratic treatise on epilepsy, On the Sacred Disease. Herodotus attributed Cambyses' erratic behavior as ruler of Egypt to either the retribution of an aggrieved god or to the fact that he had the sacred disease. Herodotus considered the possibility that the sacred disease was a somatic illness, agreeing with later Hippocratic authors that epilepsy has a natural rather than a divine cause. Archaeological evidence suggests Herodotus slanders Cambyses, and there is no corroboration that the Persian king had epilepsy or any other disease. However, the view of epilepsy as a somatic disease and uncertainty about the cause of madness shows Herodotus as a transitional figure between supernatural and naturalistic medical theories.
York GK, Steinberg DA. The Sacred Disease of Cambyses II. Arch Neurol. 2001;58(10):1702-1704. doi:10.1001/archneur.58.10.1702