Ancient DNA confirms Grand Duke Francesco de Medici (left) and his older brother, Cardinal Giovanni de Medici (right), contracted malaria.Fine Art Images/Heritage Images via Getty Images; Wikimedia Commons
Ancient DNA solves Medici murder mystery
Malaria, not poisoning, killed a prominent 16th century duke
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Ancient DNA confirms Grand Duke Francesco de Medici (left) and his older brother, Cardinal Giovanni de Medici (right), contracted malaria.Fine Art Images/Heritage Images via Getty Images; Wikimedia Commons
It was a warm October day in 1587 when Grand Duke Francesco de Medici succumbed to fever. At the time, doctors suspected malaria, but it didn’t take long for many to speculate that he had instead been poisoned by his envious younger brother, Ferdinando. Today, new evidence points the finger squarely at the original culprit, resolving the mystery for good. A study published last month in iScience examines ancient DNA from the era—including that of the duke—and confirms the mosquito-borne protozoan disease as his killer. Additional genomes analyzed in the work shed light on how malaria ravaged Renaissance-era Europe.
“This could help put an end to the ongoing debate about other causes of death such as alleged poisoning,” says Albert Zink, a paleopathologist at Ludwig Maximilian University of Munich who was not involved with the research. “The study confirms that malaria was widespread in Renaissance-era Europe and endemic in large parts of Southern and Central Europe.”
Humans have a long history with malaria stretching back tens of thousands of years. Current data suggest it arrived in Europe as early as the fourth millennium B.C.E. and later spread as far north as Finland and Russia. The Greco-Roman physician Galen regularly described encountering malarialike fevers across the Roman Empire in the 2nd century. The region’s marshes, river plains, and coastal wetlands allowed mosquitoes—and the parasites that cause malaria—to flourish. One 2016 study found evidence of the malaria parasite Plasmodium falciparum in Italy between the 1st and 2nd centuries C.E.
“Malaria was one of the most widespread infectious diseases in Renaissance Italy,” says Valentina Giuffra, a paleopathologist at the University of Pisa and co-author of the study. It remained a major public health burden in Italy and other parts of southern continental Europe until the 20th century, when land reclamation projects and mosquito control finally led to its eradication.
The Medicis’s wealth and power did not insulate them from malaria. Many members of the Florence-based dynasty, which presided over Italian banking and trade from the 15th to 18th centuries, died from the illness. In 1562, Francesco’s mother and two of his siblings, including his older brother Cardinal Giovanni de Medici, are thought to have contracted malaria during a trip to coastal Tuscany, near Pisa. They each died about a month after the outing.
To better understand how malaria impacted people in the region, including the Medicis, Giuffra and her colleagues turned to DNA from three of Francesco’s ribs and one of Giovanni’s. They also collected DNA from nine other known ancient malaria-bearing samples from remains found throughout Europe, Asia, and the Americas to try to pin down which strain killed the Medicis.
Genetic analyses revealed that Franscesco harbored the mitochondrial DNA (mtDNA) of two malarial species, P. falciparum and P. malariae, confirming he had contracted the disease. But Giovanni’s remains revealed mtDNA from a strain of P. falciparum with two novel mutations, introducing a strain of the deadly variant never seen before.
“We were incredibly thrilled to uncover distinct DNA fragments of Plasmodium falciparum still lingering in the samples,” says Serena Tucci, a paleopathologist at Yale University and lead author of the study.
The new strain found in Giovanni is closely related to lineages that had existed for centuries in Italy, Austria, France, Spain, Taiwan, and the Caribbean, Giuffra says.
Even now, P. falciparum is the deadliest species that causes malaria. In 2024 alone, it was responsible for an estimated 280 million infections and over half a million deaths. By confirming the species’ presence in Renaissance Italy, Zink says the study suggests that Florence and other Italian city-states likely suffered many more malaria-related fatalities than their northern neighbors, where less lethal, cold-tolerant variants of the parasite thrived.
Antonio de Dios Martinez, an archaeologist and ancient DNA expert at the University of Tartu who was not involved with the research, says the study does more than provide genetic evidence of past malarial infections. It also helps solve a centuries-old cold case, by confirming the Medici brothers died of natural causes—exonerating Francesco’s envious little brother of murder in the process. “The success of this approach is remarkable,” he says.
Tucci agrees. “Sometimes,” she says, “working on ancient DNA truly feels like looking directly through the keyhole of history.”
Source: https://www.science.org
