Ancient-DNA analysis solves 500-year-old mystery of what killed 2 Medici brothers
Two brothers from the wealthy and powerful Medici family died of malaria and were not poisoned as was rumored, archaeologists have confirmed. dna Analysis of the brothers’ skeletons. The analysis also revealed a unique, mutated strain malaria This could be the key to understanding the evolution of the disease in Europe.
The Medici family came to power in the 15th century by creating the largest bank in Europe. The family used their extraordinary wealth to finance renaissance artist and to start a political dynasty that eventually included several dukes, four popes, and two queens of France.
In the 16th century, cosimo i As Grand Duke he took over the whole of Tuscany. But within a period of 25 years, at least five members of his family died of high fever. This gave rise to the rumor that some of them were poisoned with arsenic by another family member, although most believed he died of malaria.
To get to the bottom of the 500-year-old Medici cold case, an international group of researchers conducted DNA testing on the bones of two of Cosimo I’s sons: Cardinal Giovanni de’ Medici and Grand Duke Francesco I de’ Medici. Plasmodium falciparumThe parasite that causes the most deadly form of malaria and which is spread by mosquitoes.
Researchers extracted ancient DNA from the bones of Cardinal Giovanni, who died in 1562 at the age of 19, the same month as his mother and younger brother Garzia, and from the bones of Grand Duke Francesco I, who died with his wife in 1587 at the age of 46. The team’s study was published online June 17 in the journal iscience.
Due to the almost simultaneous deaths of Grand Duke Francesco I and his wife, a rumor spread that another brother had poisoned them due to a long-standing feud. But it was known that the Medici often visited him Family villas in marshy and swampy areas Of Tuscany, where malaria was prevalent until the 20th century.
Researchers found evidence of this P. falciparum The bones of both Medici brothers were found, confirming reports from court physicians of the time that both brothers were ill with “Tertian fever”, a type of high fever that returns every three days and is the hallmark of malaria. Medical reports also revealed that the brothers were treated by bloodletting.
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Name plate of the tomb of Grand Duke Francesco de’ Medici, who died of malaria in 1587.
(Image credit: Courtesy of University of Pisa)
“We can now say with scientific certainty that Grand Duke Francesco de Medici died not from poison, but from malaria,” study co-authors Valentina GiuffraA medical historian at the University of Pisa said in a statement.
But the ancient-DNA study had two additional surprises.
The bones of the Grand Duke were not only positive P. falciparum but also for plasmodium malariaA different parasite species that also causes malaria in humans suggests that both species contributed to the serious illness that killed him and his wife.
Cardinal Giovanni, on the other hand, had P. falciparumBut the specific strain with which he was infected was previously unknown. The strain is similar to strains found in ancient and early modern Europe, but with two mutations researchers had never seen before, they wrote in the study.
“The study of ancient DNA not only provides us with the opportunity to diagnose malaria in the remains of individuals from the past, but it also provides us a window to understand the evolution of malaria species, Plasmodium falciparum In this case, that could help scientists better understand how the pathogen adapts over time,” says the first author of the study. Alexander Ochoaan evolutionary biologist at Yale University said in the statement.
The researchers wrote in the study that further analysis of the brothers’ bones is needed to determine the evolutionary relationship between the malaria strains.
Ochoa, A., Miller, S.L., Reilly, P.F., Fornaciari, G., Fornaciari, A., Ricomi, G., Giuffra, V., Caccone, A., Tucci, S. (2026). Ancient DNA analysis of remains of the Medici family (16th century) provides insight into genetic diversity Plasmodium falciparum. iScience 29(7). https://doi.org/10.1016/j.isci.2026.116371
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