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Heavy Metals

The mysterious death of Francesco I de' Medici and Bianca Cappello: an arsenic murder?

BMJ 2006; 333 doi: (Published 21 December 2006) Cite this as: BMJ 2006;333:1299
  1. Francesco Mari, chair of forensic toxicology1,
  2. Aldo Polettini, chair of forensic toxicology2,
  3. Donatella Lippi, chair of history of medicine1,
  4. Elisabetta Bertol, chair of forensic toxicology1
  1. 1Department of Anatomy, Histology, and Legal Medicine, University of Florence, 50134 Florence, Italy
  2. 2Department of Legal Medicine and Public Health, University of Pavia, 27100 Pavia, Italy
  1. Correspondence to: F Mari Francesco.mari{at}
  • Accepted 17 June 2006

Modern analytical techniques have allowed re-evaluation of the cause of death of Francesco I de' Medici and his wife, Bianca Cappello. It now seems that the grand-ducal couple died of acute arsenic poisoning and not malaria as previously believed

Soon after the sudden and simultaneous deaths of Francesco I de' Medici, Grand Duke of Tuscany, and his wife, Bianca Cappello, in October 1587, rumours spread that the two had been murdered by Francesco's brother, Cardinal Ferdinando.1 2 Apparently, Ferdinando had a very good motive to kill his brother and the woman that Francesco had loved and then married after the death of his first wife the Grand Duchess Giovanna of Austria. Ferdinando was at risk of being excluded from the succession if Francesco's illegitimate son Don Antonio was to inherit the title of Grand Duke or, even worse, if Bianca, who was no longer able to have children, was to falsify the birth of an heir.

Deaths of Francesco and Bianca

A couple of weeks after Ferdinando came to the villa at Poggio a Caiano, in the surroundings of Florence, where Francesco and Bianca lived, the couple suddenly fell ill; they died 11 days later, a few hours apart. The behaviour of Ferdinando during Francesco's final days, and after his death as well, raised more than a suspicion about his involvement in his brother's illness. He took charge of the entire matter, drawing up all the medical bulletins and minimising the gravity of his brother's state of health in the dispatches sent to the Holy See. He stressed that his brother's illness had to be attributed solely to his imprudent eating habits and that Bianca's illness was caused by the grief she felt for her husband's condition. He did his best to raise an impenetrable wall of isolation around Francesco and Bianca so that …

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