Louis I, le Debonnaire (the Compliant), or the Pious, king of the Franks and emperor of the West, born at Casseneuil, Aquitania, in 778, died at Ingelheim, near Mentz, June 20, 840. He was the son of Charlemagne, received when a child the title of king of Aquitania. and in 813 was associated in the imperial dignity with his father, whom he succeeded in the following year. On his accession he permitted the Saxons, whom Charlemagne had transported W. of the Rhine, to return to their own country. Animated by justice and full of good intentions, he tried at first to reform his own family, the court, the clergy, and the provincial administration; but his vacillating disposition unfitted him for the task, and finally brought misery upon him and disorder upon the empire. In 817, yielding to the request of his sons, he shared with them the government of his vast dominions, giving Aquitania to Pepin, Bavaria to Louis, and Italy to Lothaire. His nephew Bernard, being thus deprived of the latter kingdom, which he had inherited from his father, revolted against him, was defeated, taken prisoner, had his eyes put out, and died in consequence.

The emperor, under the impulse of remorse and the reproaches of the bishops, subjected himself to a public penance in a national assembly at Attigny in 822. Having had a fourth son by his second wife, Judith of Bavaria, he formed for him, at the diet of Worms in 829, a new kingdom out of the countries he had already distributed among the three eldest sons; these, being dissatisfied with this arrangement, revolted against their father, whom his partiality to his wife and her reputed paramour Bernard, duke of Septimania, had made unpopular. They seized his person, and had him deposed, while Judith was confined to a convent. Bernard escaped. The people of Germany stood by the emperor, and in 830 restored him to his throne in a general assembly at Nimeguen. Another revolt broke out in 832, Pope Gregory IV. siding with the insurgents. Louis marched against' them, but was betrayed by his own army at Rothfeld, and delivered up to Lothaire, who, without the consent of his brothers, subjected the unhappy old man to indignities, had him brought before a council at Com-piegne, over which his personal enemy Ebbo, archbishop of Rheims, presided, charged him with a number of crimes which he was obliged to confess aloud, and finally caused him to be degraded.

Louis and Pepin, moved partly by pity, partly by jealousy of their brother, then took their father's part, and restored to him the crown in the states general held at Die-denhofen (Thionville) in 835. The emperor at once forgave Lothaire, who came to make submission. His partiality for his youngest son Charles, to whom he wished to bequeath more than his full share of territory, again involved him in trouble. At the diet of Worms (839), Pepin being dead, the emperor proposed to divide his whole empire between Lothaire and Charles, upon which Louis, aided by his nephew Pepin II., took arms again. The emperor marched against them, but before reaching the rebels he was seized with an illness which proved fatal. With the reign of Louis le Debonnaire commenced the dissolution of the Carlovingian empire. - See Bernhard Simeon, Jahrbucher des frankuchen Reichs untcr Ludicig dem Frommen (1874).