Lothair I

Emperor of the Carolingian Empire from 817 to 855

Born in 795 at Altdorf, Lothair I emerged as a central figure in the disintegration of the Carolingian Empire. As the eldest son of Louis the Pious, his political trajectory was defined by repeated dynastic conflicts with his brothers and father, eventually leading to the significant territorial restructuring formalized through the Treaty of Verdun in 843.

Rise to Imperial Status

Lothair began his administrative career as the duke of Bavaria. In 817, his father issued the Ordinatio Imperii, designating him as the principal heir and joint emperor. He was crowned in Rome by Pope Paschal I in 823. During this period, he promulgated the Constitutio Romana in 824, a statute that established the legal relationship between the papacy and the imperial throne by asserting secular authority.

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Dynastic Conflicts and Civil War

The stability of the empire fractured as Lothair led multiple rebellions against his father, Louis the Pious, alongside his brothers Pepin I of Aquitaine and Louis the German. These conflicts persisted until his father’s death in 840. Lothair claimed the entire empire, which triggered a war with Louis the German and his half-brother Charles the Bald. Their forces defeated him at the Battle of Fontenay-en-Puisaye on 25 June 841.

The Treaty of Verdun and Territorial Rule

Following years of negotiation, the Treaty of Verdun was signed in August 843. Lothair retained the imperial title and was granted a territory spanning from the North Sea to the Mediterranean, encompassing Lorraine, Alsace, Burgundy, and Provence. He subsequently ceded the Kingdom of Italy to his eldest son, Louis II, while attempting to defend his own fractured holdings against Viking and Saracen incursions.

Abdication and Final Days

In 855, suffering from failing health, Lothair renounced his political responsibilities. He divided his remaining lands among his sons Louis II, Lothair II, and Charles through the Treaty of Prüm. On 23 September 855, he entered the monastery of Prüm, where he died six days later. His remains were discovered at the site in 1860.

Fast facts

Questions readers ask

What territories did Lothair I control after the Treaty of Verdun?

He ruled a central strip of the empire stretching from the North Sea to the Mediterranean, including northern Italy, Lorraine, Alsace, Burgundy, and Provence.

Who were his primary political rivals?

His primary rivals were his father, Louis the Pious, and his brothers, Louis the German and Charles the Bald.

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