A study using ancient DNA extracted from the remains of two Renaissance Medici brothers—Grand Duke Francesco I and Cardinal Giovanni—finds that both died from malaria. The genetic analysis confirms infection with the malaria parasite at the time of death, resolving a long-standing question about what killed the brothers. Reporting on the findings also notes that the researchers identify characteristics of the parasite that provide insight into its evolution, including evidence of an older strain compared with what is commonly referenced today. The results are presented as clarifying the brothers’ medical history and challenging earlier rumors that suggested poisoning or other causes. While the study centers on the cause of death based on genetic evidence from bone remains, it is also framed as contributing to broader understanding of how malaria strains develop and spread over time. The findings collectively indicate that infectious disease, rather than foul play, is the most consistent explanation supported by the available ancient genetic material.