The story of France’s Louis IX, known as Saint Louis to Catholics, is that the pious monarch died of plague while leading the Eighth Crusade, an attempt to shore up control of the Holy Land in the name of Christianity. But a new study of Louis’ jawbone suggests it wasn’t plague that took the king down in the summer of 1270 A.D. but a stubborn refusal to eat the local food in Tunisia during his long journey.
Agence-France Presse reports that an international collaboration of researchers came to that conclusion after taking a look at Louis’ jawbone, which is buried in Notre Dame Cathedral. Using radiocarbon dating, the team first established that the jaw was about 50 years too old to belong to the warrior-king. But adjusting for the fact that Louis is known to have consisted mostly on a diet of fish, which would have skewed the carbon ratios in his bones, they said it's reasonable to believe the bones are from the right time period. They also compared the jaw shape to sculptures of the king, finding that it appeared the match.
Looking at the jaw, the team saw very strong signs that Louis suffered from a bad case of scurvy, a disease caused by a lack of vitamin C in the diet that attacks the gums and bones. The research appears in the Journal of Stomatology, Oral and Maxillofacial Surgery.
The historical record supports their diagnosis. The researchers say that contemporary accounts of Louis’s demise recount the king spitting out bits of gum and teeth, consistent with what was found in the mandible and signs of late-stage scurvy.
The real head-scratcher is why the king would suffer from such a disease when it’s likely plenty of fresh fruit and vegetables, which could have saved him, were available in the Tunisian countryside.
French forensic pathologist and study co-author Philippe Charlier tells AFP that it was likely a combo of poor logistics and excess piety that sealed the king’s fate. “His diet wasn’t very balanced,” he says of the king. “He put himself through all manner of penances, and fasting. Nor was the crusade as well prepared as it should have been. They did not take water with them or fruit and vegetables.”
And, it appears, his army did not supplement their rations with local produce. It wasn’t just Louis that suffered. While laying siege to the city of Tunis, up to one sixth of the Crusader army died, including Louis’ son John Tristan, may have also died of the disease.
Rafi Letzer at LiveScience reports that Jean de Joinville, who chronicled the crusade, described the crusaders' gory ordeal. “Our army suffered from gum necrosis [dead gums],” he wrote, "and the barbers [doctors] had to cut the necrotizing tissue in order to allow the men to chew the meat and swallow. And it was a pity to hear the soldiers shouting and crying like women in labor when their gums were cut.”
Scurvy wasn’t the only disease they suffered from. Both armies during the battle were struck with trench disease, a pathogen transmitted by lice that also plagued armies during World War I and World War II.
Scurvy may not have been the primary cause of Louis’ death, but it likely weakened him enough to allow another pathogen to finish him off. There are some reports that Louis also suffered from dysentery around the time of his death.
The researchers doubt the king’s death was caused by plague. “Tradition has conserved a cause of death as plague but this could be related to a bad translation of the ancient word ‘pestilence,’" the authors write in the paper.
“That he died of the plague is still there in the history books,” Charlier tells AFP, “and modern science is there to rectify that.”
Going forward, the team hopes to definitely answer what bug killed the king off by examining parts of his stomach, which was cut up and boiled in wine to preserve it before it was shipped back to Paris with the rest of his remains.
While Louis’ piety and ministrations to the poor and lepers earned him sainthood, his reputation as a military leader is decidedly mixed. In 1242, he repulsed an English incursion into France by Henry III, though it was less battle, more standoff.
In 1244, after suffering from a bout of malaria, the young king decided to lead the Seventh Crusade to the Holy Lands to lend support to Christian Kingdoms established by previous crusades, which had recently fallen to Egyptian Mamluk armies.
He set out with a fleet of 100 ships, carrying 35,000 soldiers to fight in 1248. The idea was to attack Egypt, then trade captive Egyptian cities for those in the Holy Land. But after an auspicious beginning in which they captured various strongholds on the way to Cairo, the exhausted army was struck by plague at Mansourah. As they retreated back up the river, the Egyptians caught up, taking Louis and many high nobles into captivity.
Louis was ransomed and the original plan had to be abandoned. But instead of returning home, he went to the Crusader kingdom of Acre, in present-day Israel, where he arranged alliances and fortified Christian positions in the area for four years before returning to France.
Sixteen years later, the Crusader States were once again threatened, this time by Mongols coming from the east. Louis decided the time was right to strike, and planned to cross the Mediterranean and capture Tunis, which he would then be able to use as a base to attack Egypt and secure the Christian states as part of the Eighth Crusade. But everything fell apart on the first leg of the venture; Louis died, and the armies returned to Europe after negotiating a deal with the Emir of Tunis. In 1291, the city of Acre finally fell, ending the brief, turbulent history of Crusader states in the Near East.