It has been suggested in the medical literature that in the last period of his life King David (c. 1040–970 BCE) suffered from dementia, osteoporosis, hyperparathyroidism, Parkinson’s disease, autonomic neuropathy, major depression, and malignancy. The goal of this study was to identify, based on the “Succession Narrative (SN),” a historically objective section of the Old Testament, the clinical syndrome presented by King David and to determine whether an impaired decision making capacity may have been manipulated by his courtiers to influence his succession’s politics. The “SN” indicates that besides forgetfulness and trouble in thinking, King David suffered from marked cold intolerance and sexual dysfunction. The symptom triad consisting of cognitive impairment, cold intolerance, and sexual dysfunction is more strongly suggestive of hypothyroidism than of any other diagnoses proposed in the medical literature so far. We hypothesized that hypothyroidism was the underlying cause of the elderly King David’s clinical picture and that his sometimes troubled thinking was successfully manipulated by the courtiers to favor his son Solomon’s accession to the throne, with profound historical consequences.