DNA From Louis XIV’s Mummified Heart Points To Fungal Infection, Not Gangrene

Researchers re-examining a fragment of Louis XIV’s mummified heart say modern DNA and microscopic analyses point to a fungal infection — not the gangrene long recorded in contemporary accounts — as the likely cause of the Sun King’s death on Sept. 1, 1715.

New forensic evidence. A team led by French pathologist Philippe Charlier analysed tissue and blood residues from a heart fragment kept at the Basilica of Saint-Denis. Instead of the bacteria typically associated with gangrene, the scientists reported finding fungal material consistent with a chronic subcutaneous mycosis. Their findings were reported by U.K. and French outlets including The Times and Le Parisien.

What the analysis found

The researchers identified fungal residues around the heart fragment and interpreted the pattern as compatible with chromoblastomycosis, a chronic skin infection caused by pigmented (dematiaceous) fungi. According to the team, that infection could have advanced to septicemia (blood poisoning), explaining the king’s rapid decline in the weeks before his death.

Historical context and access

For centuries, contemporaneous medical notes listed gangrene as Louis XIV’s final illness. Chroniclers such as the Duke of Saint-Simon wrote of the king’s stoic acceptance of his worsening condition. The recent investigation proceeded after descendants of the king — Jean d’Orléans and Louis-Alphonse de Bourbon (the Duke of Anjou) — granted researchers permission to sample the relic.

Why this matters

"By analysing the blood residues that were still present around the heart, we realised that it wasn’t bacteria at all, but rather fungi," said Charlier, summarising why the team now favours a fungal-sepsis hypothesis.

The results illustrate how modern forensic methods can revise long-standing historical medical diagnoses. While uncertainty remains—ancient tissue is difficult to interpret definitively—the presence of fungal material around the heart fragment provides a plausible alternative explanation to gangrene for the monarch’s final illness and suffering.

Sources: Reporting in The Times and Le Parisien; analysis led by Philippe Charlier; heart fragment kept at the Basilica of Saint-Denis.