DNA study suggests malaria, not arsenic poisoning, killed Medici ruler Francesco I and wife Bianca in 1587

Scientists say new genetic evidence may resolve a 400-year mystery over the deaths of Grand Duke Francesco I de’ Medici and Bianca Cappello. Despite longstanding rumors of arsenic poisoning tied to a dynastic power struggle, the findings support malaria as the likely cause.

The study shows how modern paleogenomics can revisit politically charged historical deaths and separate rumor from biological evidence. It also highlights a broader trend: ancient DNA is increasingly being used to reexamine famous cases where written records and folklore remain ambiguous.