His most grievous sins included cloistering his relations to remove them as rivals to his succession in 814, mortally blinding his nephew for revolt, breaking a sworn treaty with his sons, and allowing his marriage to deteriorate to the point of his wife having an affair with a courtier.

Louis I is known in Germany as ‘the Pious’, but in France as le Débonnaire; both sobriquets capture aspects of his behaviour. He was sufficiently sinful to require three rites of penance during his reign, yet devout enough to perform them. His most grievous sins included cloistering his relations to remove them as rivals to his succession in 814, mortally blinding his nephew for revolt, breaking a sworn treaty with his sons, and allowing his marriage to deteriorate to the point of his wife having an affair with a courtier. Interpretations differ whether the Carolingian bishops regarded him as an errant member of their flock or used the rites of penance a show trials to discredit him politically.

P.H. Wilson, The Holy Roman Empire (2016), 30