DNA Analysis Reveals Medici Duke Died of Malaria, Not Poison

A new study published in iScience debunks centuries-old rumors that Francesco I de' Medici, Grand Duke of Tuscany, was poisoned by his brother Ferdinando in 1587. Instead, DNA analysis of Francesco's remains shows he died of malaria, caused by Plasmodium falciparum and P. malariae parasites. The study also found that his brother Giovanni, who died in 1562, was infected with a previously uncharacterized strain of P. falciparum. Researchers extracted DNA from rib bones of Francesco and Giovanni, interred at the Medici Chapels in Florence. The findings confirm historical accounts of malaria as the cause of death, according to co-author Valentina Giuffra of the University of Pisa. Senior author Serena Tucci of Yale University noted the study demonstrates how ancient DNA methods can map pathogen history. Francesco fell ill while hunting in Tuscany and died 11 days later; his wife Bianca Cappello died the next day. Ferdinando, who succeeded Francesco, had been suspected due to his motive and presence at the deathbed, but the brothers had reconciled two weeks prior.