Louis the Pious, also called the Fair and the Debonaire, was King of the Franks and co-emperor with his father, Charlemagne, from 813. He was also King of Aquitaine from 781. As the only surviving son of Charlemagne and Hildegard, he became the sole ruler of the Franks after his father's death in 814. He held this position until his death in 840, save for November 833 to March 834 when Louis was deposed. April 20, 778 – June 24, 840; died at 62. Alive at the same time as Muḥammad ibn Musa al-Khwarizmi, Abu Nuwas, Ādi Shankara, Al-Shafi'i, and Charlemagne. Wiki link