Research Notes:

He is named, and his parentage recorded, in the Gesta Mettensium, which specifies that he was his parents' third son, born a twin with his brother Hlothar.

Crowned King of the Aquitainians in Rome 15 Apr 781 by Pope Hadrian I. His armies occupied Girona, Urgel and Cerdanya in 785 and besieged Barcelona in 802, establishing the "March of Spain". At the partition of territories agreed at Thionville in 806, he was designated sovereign of Aquitaine, Gascony, Septimania, Provence and southern Burgundy.

His father named him as his successor at Aix-la-Chapelle, crowning him as joint emperor 11 Sep 813. On his father's death, he adopted the title Emperor LOUIS I “der Fromme/le Pieux” 2 Feb 814, and was crowned at Reims [Jul/Aug] 816 by Pope Stephen IV. He did not use the titles king of the Franks or king of Italy so as to emphasise the unity of the empire. He promulgated the Ordinatio Imperii at Worms in 817, which established his eldest son as his heir, his younger sons having a subordinate status, a decision which was eventually to lead to civil war between his sons. His nephew Bernard King of Italy, ignored in the Ordinatio Imperii, rebelled against his uncle, but was defeated and killed. After his death, Italy was placed under the direct rule of the emperor.

Emperor Louis crowned his son Lothaire as joint emperor at Aix-la-Chapelle in Jul 817, his primary status over his brothers being confirmed once more at the assembly of Nijmegen 1 May 821. In Nov 824, Emperor Louis placed Pope Eugene II under his protection, effectively subordinating the papal role to that of the emperor. The birth of his son Charles by his second marriage in 823 worsened relations with his sons by his first marriage, the tension being further increased when Emperor Louis invested Charles with Alemannia, Rhætia, Alsace and part of Burgundy at Worms in Aug 829, reducing the territory of his oldest son Lothaire to Italy. His older sons revolted in Mar 830 and captured their father at Compiègne, forcing him to revert to the 817 constitutional arrangements. However, Emperor Louis reasserted his authority at the assemblies of Nijmegen in Oct 830 and Aix-la-Chapelle in Feb 831, depriving Lothaire of the imperial title and relegating him once more to Italy. A further revolt of the brothers followed. Emperor Louis was defeated and deposed by his sons at Compiègne 1 Oct 833. He was exiled to the monastery of Saint-Médard de Soissons. His eldest son Lothaire declared himself sole emperor but was soon overthrown by his brothers Pépin and Louis, who freed their father. Emperor Louis was crowned once more at Metz 28 Feb 835. He proposed yet another partition of territories in favour of his son Charles at the assembly of Aix-la-Chapelle in 837, implemented at the assembly of Worms 28 May 839 when he installed his sons Lothaire and Charles jointly, setting aside the claims of his sons Pépin and Louis. This naturally led to revolts by Pépin in Aquitaine and Louis in Germany, which their father was in the process of suppressing when he died.

The Annales Fuldenses record the death "in insulam quondam Rheni fluminis prope Ingilenheim XII Kal Iul 840" of Emperor Louis and his burial "Mettis civitatem…in basilica sancti Arnulfi". The necrology of Prüm records the death "840 12 Kal Iul" of "Ludvicus imperator". The necrology of St Gall records the death "XII Kal Jul" of "Hludowicus imperator in insula Rheni quiæ est sita iuxta palatium Ingelheim". The Obituaire de Notre-Dame de Paris records the death "XII Kal Jul" of "Ludovicus imperator". The necrology of the abbey of Saint-Denis records the death "XII Kal Jul" of "Ludovicus imperator". The necrology of Saint-Germain-des-Prés records the death 840 “XII Kal Jul” of “Hludovuici imperatoris”. ¹