Ancient DNA Confirms Malaria Killed Renaissance Duke

Researchers in Italy and the United States analyzed ancient DNA to determine the cause of death of Francesco de’ Medici, Grand Duke of Tuscany, who died in 1587. For centuries, speculation surrounded his death, with some believing his brother, Ferdinando, poisoned him to seize power.

Previous studies suggested arsenic poisoning or malaria, but lacked definitive proof. The new research, published in iScience, examined DNA extracted from Francesco’s ribs and compared it to samples from his brother Giovanni, who also died of malaria, and other historical malaria victims from Europe, Asia, and America.

The team successfully isolated mitochondrial DNA of Plasmodium, the malaria parasite, in all samples. Francesco de’ Medici had contracted two strains of malaria, P. falciparum and P. malariae, at the time of his death.

Giovanni carried only P. falciparum, but with unique mutations. This evidence strongly supports the official cause of death and refutes theories of foul play.