DNA analysis shows Francesco I de’ Medici and Bianca Cappello died of malaria, not poisoning

Researchers from the University of Pisa and Yale re‑examined the skeletal remains of Francesco I de’ Medici, Grand Duke of Florence, and his wife Bianca Cappello, who died in 1587. Ancient DNA testing identified genetic traces of the malaria parasites Plasmodium falciparum and Plasmodium malariae in both sets of bones, indicating that the couple succumbed to malaria rather than to an alleged arsenic poisoning. The study, part of the Medici Project that began in 2004 and has examined 49 Medici tombs, provides decisive evidence that the long‑standing theory of fraternal brother Ferdinand orchestrating a lethal poison plot is unlikely. Nonetheless, some scholars note that poisoning cannot be completely ruled out, as the presence of malaria does not preclude other causes. "The DNA is conclusive," said Valentina Giuffra, professor of medical history at the University of Pisa, adding that the findings settle a debate that has persisted for centuries. The couple fell ill at the Medici villa in Poggio a Caiano, an area of marshes and rice fields that offered ideal breeding grounds for malaria‑carrying mosquitoes.