Answer
Dysentery, a severe intestinal infection, claimed the life of King Louis VIII of France in 1226. Spread through contaminated food or water, dysentery causes inflammation and ulceration of the intestines, leading to severe diarrhea, abdominal pain, and dehydration. Despite medical interventions available at the time, Louis VIII succumbed to the disease at the age of 39, leaving a profound impact on the French monarchy and the ongoing Albigensian Crusade.