Analysis of information sources in references of the Wikipedia article "Charles the Fat" in English language version.
Charles suffered excruciating pains in his head and attributed it to some sort of diabolic possession, for which he was exorcised, but the pain continued. Then he had incisions made in his head to get rid of the devil, but the pain only grew worse. Among other delusions, he suspected his wife of misconduct with Luitward, bishop of Vercelli. She demanded to clear her character, either by having a champion to fight for her or by some other ordeal. The trial consisted of the accused being wrapped in linen cloth soaked with inflammable liquid and set on fire at the four corners. It was burnt away to nothing, and the innocent queen remained unhurt. Thus was her innocence proved.
