Live Science8%
Ancient-DNA analysis solves 500-year-old mystery of what killed 2 Medici brothers 30%
By Kristina Killgrove15%
7/1/2026, 1:50:26 PM
BS Summary: This article contains 23 faulty reasoning types, including Biased Writer Voice, Optimism Bias, and Confirmation Bias, with Appeal to Authority as the most egregious example at 32.3% saturation with 146 hits. Analysis detected 1,084 faulty-reasoning hits from 452 analyzed words, generating a BS Score of 39.7% and a BS Rank of 30% (15,487 of 21,887 articles). This article is better (less manipulative) than 70.80% of the article peer group.
Two brothers from the wealthy and powerful Medici family died of malaria and were not poisoned as a rumor had suggested, archaeologists have confirmed based on a DNA analysis of the brothers' skeletons.
The analysis also revealed a unique, mutated strain of malaria that may hold the key to understanding the evolution of the disease in Europe.
The Medici family rose to power in the 15th century by creating the largest bank in Europe.
The family used their extraordinary wealth to fund Renaissance artists and to start a political dynasty that eventually included numerous dukes, four popes and two queens of France.
To get to the bottom of the 500-year-old Medici cold case, an international group of researchers tested the bones of two of Cosimo I's sons: Cardinal Giovanni de' Medici and Grand Duke Francesco I de' Medici, for the DNA of Plasmodium falciparum, the parasite that causes the deadliest form of malaria and that is transmitted by mosquitoes.
The researchers extracted ancient DNA from the bones of Cardinal Giovanni, who died in 1562 at age 19 in the same month as his mother and younger brother Garzia, and from Grand Duke Francesco I, who died at age 46 in 1587 along with his wife.
The team's study was published online June 17 in the journal iScience.
"Now we can say with scientific certainty that malaria, not poisoning, killed Grand Duke Francesco de Medici," study co-author Valentina Giuffra, a medical historian at the University of Pisa, said in a statement.
But the ancient-DNA study held two additional surprises.
The Grand Duke's bones were positive not only for P. falciparum but also for Plasmodium malariae, a different parasite species that also causes malaria in humans, suggesting that both species contributed to the severe illness that killed him and his wife.
Cardinal Giovanni, on the other hand, had only P. falciparum, but the specific strain that infected him was previously unknown.
The strain is similar to those found in ancient and early modern Europe, but with two mutations the researchers had never seen before, they wrote in the study.
"The study of ancient DNA offers us an opportunity not only to diagnose malaria in the remains of individuals from the past, but it also offers us a window for understanding the evolution of malaria species, Plasmodium falciparum in this case, which can help scientists better understand how the pathogen adapts over time," study first author Alexander Ochoa, an evolutionary biologist at Yale University, said in the statement.
Further analysis of the brothers' bones is needed to determine the evolutionary relationship between the strains of malaria they carried, the researchers wrote in the study.
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100%flagged-word coverageValentina Giuffra
33 attributed words33% of attributed speech79% writer coverage
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