Charles III, known as Charles the Fat, was Emperor of the Carolingian Empire and King of West Francia, East Francia, and Italy in the late 9th century. Grandson of Charlemagne, he briefly reunited much of the empire but was seen as an ineffective ruler. His inability to defend against Viking raids and his passive leadership led to his deposition in 888. Plagued by illness and political strife, his reign marked the decline of Carolingian power. He died shortly after, leaving the empire in chaos.