text: One chronicle declares that those envious of this ruler could find only one fault in him - that he was too merciful.
full_question: One chronicle declares that those envious of this ruler could find only one fault in him - that he was too merciful. That chronicle of this ruler's life was written by a figure known only as "the Astronomer," while a lengthy poem honoring this ruler's deeds was written by Ermoldus Nigellus, or Ermold the Black, whom he may have exiled. This ruler governed monasteries in his land according to the Codex Regularum developed by Benedict of Aniane, and a biography of his life was written by Thegan of Trier. His daughter Gisela was gifted the nunnery of San Salvatore, the former residence of his second wife Judith of Bavaria. He was briefly revolted against by his librarian Ebbo, the Archbishop of Reims, who propped up this man's son Pepin of Aquitaine. Later on, he designated his youngest son Charles the Bald to receive Aquitaine, incurring the wrath of his other son Lothair. His lands were finally divided amongst his heirs by the Treaty of Verdun. For 10 points, name this son and successor of Charlemagne.
first_sentence: One chronicle declares that those envious of this ruler could find only one fault in him - that he was too merciful.
raw_answer: Louis the Pious [or Louis I; or Louis the Fair; or Louis the Debonaire; prompt on "Louis"]