Pepin I, king of Aquitania, born about 802, died in 838. The second son of Louis le De-bonnaire by his first wife, he received from him in 817 the kingdom of Aquitania, while his youngest brother Louis had Bavaria, and the eldest, Lothaire, was associated in the government of the empire. In 829, when the emperor wished to change this arrangement in order to provide for Charles, who had been born to him by his second wife, Judith of Bavaria, Pepin joined his brothers in a rebellion against their father, whom they confined in a monastery; but soon becoming dissatisfied with Lothaire, who had seized upon the imperial authority, Pepin participated in the national assembly held in 830 at Nimeguen, which restored Louis to his throne. His father now threatening to take Aquitania from him, he rebelled again in 832, and in 833 all the three princes marched their troops to Alsace, took the emperor prisoner through the treachery of his own troops, conveyed him to Com-piegne, and forced him to do solemn penance.

But shortly after Pepin and Louis of Bavaria, disgusted once more with their elder brother's behavior, released their father and again acknowledged his supremacy. - Pepin II., Pepin's eldest son, bereft of his inheritance, which was granted to Charles the Bald, the youngest son of Louis le Debonnaire, was nevertheless acknowledged as king by the Aquitanians. In 840 he joined his uncle Lo-thaire in his contest against Charles the Bald and Louis the German, was defeated with him at Fontenay in 841, and once more, by the treaty of Verdun in 843,, deprived of his kingdom. He still held his ground, forced Count "William of Toulouse into submission, routed the army of Charles the Bald near Angouleme in 844, and finally in 845 obliged his uncle to grant him the best part of Aquitania as a fief. But his popularity among the Aquitanians vanished when he allied himself with the Northmen. Abandoned both by his subjects and his allies, he took refuge in Gascony, but was betrayed into the hands of Charles the Bald in 852. Imprisoned in a monastery, he escaped in 854, induced a number of Aquitanians to rise in his behalf, again procured the assistance of the Northmen, and in 857 obliged Charles to grant him lands.

But in a last attempt to take Toulouse at the head of the Northmen in 864, he fell into an ambush, was sent to Pistes, where he was sentenced to death by the lords of the kingdom, and was imprisoned at Senlis, where he soon died.