Louis the Pious (Latin: Hludowicus Pius; French: Louis le Pieux; German: Ludwig der Fromme; 778 – 20 June 840), 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.
During his reign in Aquitaine, Louis was charged with the defence of the empire's southwestern frontier. He conquered Barcelona from the Emirate of Córdoba in 801 and asserted Frankish authority over Pamplona and the Basques south of the Pyrenees in 812. As emperor, he included his adult sons, Lothair, Pepin and Louis, in the government and sought to establish a suitable division of the realm among them. The first decade of his reign was characterised by several tragedies and embarrassments, notably the brutal treatment of his nephew Bernard of Italy for which Louis atoned in a public act of self-debasement.
In the 830s his empire was torn by civil war between his sons that was only exacerbated by Louis's attempts to include his son Charles by his second wife in the succession plans. Though his reign ended on a high note, with order largely restored to his empire, it was followed by three years of civil war. Louis is generally compared unfavourably to his father but faced distinctly different problems.
Louis was born in 778, while his father Charlemagne was on campaign through the Pyrenees, at the Carolingian villa of Cassinogilum, according to Einhard and the anonymous chronicler called Astronomus; the place is usually identified with Chasseneuil, near Poitiers. He was the third son of Charlemagne by his wife Hildegard. He had a twin brother named Lothair, who died young. Louis and Lothair were given names from the old Merovingian dynasty, possibly to suggest a connection.
Louis was crowned King of Aquitaine as a three-year-old child in 781. In the following year he was sent to Aquitaine accompanied by regents and a court. Charlemagne constituted this sub-kingdom in order to secure the border of his realm after the destructive war against the Aquitanians and Basques under Waifar (capitulated c. 768) and later Hunald II, which culminated in the disastrous Battle of Roncesvalles (778). Charlemagne wanted Louis to grow up in the area where he was to reign. However, wary of the customs his son may have been assimilating into in Aquitaine, Charlemagne, who had remarried to Fastrada after the death of Hildegard, sent for Louis in 785. Louis presented himself in Saxony at the royal Council of Paderborn dressed in Basque costumes along with other youths in the same garment, which may have made a good impression in Toulouse, since the Basques of Vasconia were a mainstay of the Aquitanian army.
In 794, Charlemagne gave four former Gallo-Roman villas to Louis, in the thought that he would take in each in turn as winter residence: Doué, Ebreuil, Angeac and the Chasseneuil. Charlemagne's intention was to see all his sons brought up as natives of their given territories, wearing the national costume of the region and ruling by the local customs. Thus were the children sent to their respective realms at a young age. The marches—peripheral principalities—played a vital role as bulwarks against exterior threats to the empire. Louis reigned over the Spanish March. In 797, Barcelona, the largest city of the Marca, fell to the Franks when Zeid, its governor, rebelled against Córdoba and, failing, handed it to them. The Córdoban authority recaptured it in 799. However, Louis marched the entire army of his kingdom, including Gascons with their duke Sancho I of Gascony, Provençals under Leibulf, and Goths under Bera, over the Pyrenees and besieged it for seven months, wintering there from 800 to 801, when it capitulated. King Louis was formally invested with his armour in 791 at the age of fourteen. However, the princes were not given independence from central authority as Charlemagne wished to implant in them the concepts of empire and unity by sending them on remote military expeditions. Louis joined his brother Pippin at the Mezzogiorno campaign in Italy against the Duke Grimoald of Benevento at least once.
Louis was one of Charlemagne's three legitimate sons to survive infancy. His twin brother, Lothair, died during infancy. According to the Frankish custom of partible inheritance, Louis had expected to share his inheritance with his brothers, Charles the Younger, King of Neustria, and Pepin, King of Italy. In the Divisio Regnorum of 806, Charlemagne had slated Charles the Younger as his successor as ruler of the Frankish heartland of Neustria and Austrasia, while giving Pepin the Iron Crown of Lombardy, which Charlemagne possessed by conquest. To Louis's kingdom of Aquitaine, he added Septimania, Provence, and part of Burgundy. However, Charlemagne's other legitimate sons died—Pepin in 810 and Charles in 811—and Louis was crowned co-emperor with an already ailing Charlemagne in Aachen on 11 September 813. On his father's death in 814, he inherited the entire Carolingian Empire and all its possessions (with the sole exception of the kingdom of Italy; although within Louis's empire, in 813 Charlemagne had ordered that Bernard, Pepin's son, be made and called king).
While at his palace of Doué, Anjou, Louis received news of his father's death. He rushed to Aachen and crowned himself emperor to shouts of Vivat Imperator Ludovicus by the attending nobles.
Upon arriving at the imperial court in Aachen in an atmosphere of suspicion and anxiety on both sides, Louis's first act was to purge the palace of what he considered undesirable. He destroyed the old Germanic pagan tokens and texts which had been collected by Charlemagne. He further exiled members of the court he deemed morally "dissolute", including some of his own relatives.
He quickly sent all of his many unmarried (half-)sisters and nieces to nunneries in order to avoid any possible entanglements from overly powerful brothers-in-law. Sparing his illegitimate half-brothers Drogo, Hugh and Theoderic, he forced his father's cousins, Adalard and Wala to be tonsured, sending them into monastic exile at St-Philibert on the island of Noirmoutier and Corbie, respectively, despite the latter's initial loyalty.
He made Bernard, margrave of Septimania, and Ebbo, Archbishop of Reims his chief counsellors. The latter, born a serf, was raised by Louis to that office, but betrayed him later. He retained some of his father's ministers, such as Elisachar, abbot of St. Maximin near Trier, and Hildebold, Archbishop of Cologne. Later he replaced Elisachar with Hildwin, abbot of many monasteries.
He also employed Benedict of Aniane (the Second Benedict), a Septimanian Visigoth, whom he made abbot of the newly established Inden Monastery at Aix-la-Chapelle and charged him with the reform of the Frankish church. One of Benedict's primary reforms was to ensure that all religious houses in Louis's realm adhered to the Rule of Saint Benedict, named for its creator, Benedict of Nursia. From the start of his reign, his coinage imitated his father Charlemagne's portrait, which gave it an image of imperial authority and prestige. In 816, Pope Stephen IV, who had succeeded Leo III, visited Reims and again crowned Louis on Sunday 5 October. As a result, most French kings were crowned in Reims, following the custom established by Louis the Pious.
On 9 April 817, Maundy Thursday, Louis and his court were crossing a wooden gallery from the cathedral to the palace in Aachen, when the gallery collapsed, killing many. Louis, having barely survived and realizing death was imminent, began planning for his succession. Three months later among the approval of his Aachen court and the clergy he issued an imperial decree of eighteen chapters, the Ordinatio Imperii, that laid out plans for an orderly dynastic succession. The term Ordinatio Imperii is a modern (19th-century) creation. The decree is called divisio imperii in the only surviving contemporary manuscript.