 Morman's rebellion against Frankish lordship in 814 threatened the integrity of Charlemagne's empire, recently inherited by Louis the Pious.While the Bretons may have viewed the elevation of Morman as king on the death of Charlemagne as legitimate, the Frankish writers Astronomus and Ermold the Black saw it as a usurpation.Louis sent Abbot Witchar to negotiate with Morman.