The Field of Lies by Dan Jones

Between 830 and 840 a series of three major rebellions broke out in which Lewis's sons banded together to try to improve their portions of the imperial inheritance. In keeping with carolingian custom he writes many cruel murderous and disgraceful deeds were perpetrated including further further blindings drownings and exiles accusations of witchcraft and adultery leveled against Lewis's wife and empress juneth. He says that like Alexander the great before him charlemagne had built an empire that quickly proved itself possible only as an extension of one man's political self.