Queen Maria de’ Medici (1573–1642) died in a miserable, marasmic state. Infections, gangrene, weight loss, fatigue and respiratory problems suggest a progressive decompensation of a previously existing Type 2 diabetes. The lack of biochemical data, however, permits only circumstantial evidence of this hypothesis. The author proposes that the queen developed subclinical diabetes after the age of 45, when she became obese due to excessive eating and lack of exercise. With a clear familial predisposition, she could have become insulin resistant and chronically hyperglycaemic. The presence of an internal deviation of the left eye, visible on several late portraits, suggests a mononeuropathy of cranial nerve VI. Repeated skin infections and gangrene of the lower limbs during the last month of her life complete the clinical diagnosis. Hyperglycaemic ketosis with Kussmaul respiration without adequate treatment may have caused her death.
