The Treaty of Verdun

The Treaty of Verdun, concluded in August 843, was the most important political settlement of the early Middle Ages. It divided the Carolingian Empire of the Charlemagne among his three grandsons, and it did so in a way that proved more durable than any of the partitions that had preceded it. From the boundaries drawn at Verdun historians later derived the rough shape of medieval France, medieval Germany, and the Lotharingian middle kingdom that would be fought over for centuries. The treaty is therefore one of the foundational documents of European history.

The empire on the eve of partition

Charlemagne had been crowned emperor in 800 and had died in 814. He was succeeded by his only surviving son, Louis the Pious, who inherited an empire that stretched from the Pyrenees to the Elbe and from the North Sea to the heart of Italy. Louis was, in many ways, a more pious and a more conscientious ruler than his father. He took seriously the imperial title, the obligations of Christian kingship, and the duty to consult the empire’s bishops, magnates, and people. He was also less successful at keeping his empire intact.

Louis’s first wife, Ermengard of Hesbaye, bore him three sons who survived to adulthood: Lothair, Pepin, and Louis. The Divisio Imperii of 817, drafted with the help of the Benedictine abbot Benedict of Aniane, had assigned the empire to the eldest, Lothair, with his brothers as subordinate kings. The plan was undone by Louis’s second marriage. In 819 he married Judith of Bavaria, who bore him a fourth son, Charles the Bald, in 823. The birth of a fourth son shattered the careful arrangements of 817, and from 829 onward Louis tried, again and again, to find a partition that satisfied all of his children. Each attempt failed. Each failure produced a new civil war.

The civil war of 830–840

The civil war that preceded Verdun lasted more than a decade and convulsed the empire. It pitted Louis the Pious against his sons, the sons against one another, and the bishops and magnates of the empire on every side. The first crisis came in 830, when Lothair joined with the rebel Italian magnates and the disaffected Frankish aristocracy to depose his father. Louis was reinstated within weeks, but the precedent was set: the imperial dignity was no longer untouchable.

The next crisis came in 833, when Lothair and his brothers Pepin and Louis, encouraged by a group of reformist bishops, met their father at the Lügenfeld, the Field of Lies, near Colmar. The princes persuaded the army to abandon Louis, and the emperor was deposed and forced to do public penance. The humiliation, immortalized in the courtly poem De malis quae Lotharius rex gessit, was reversed the following year when the magnates returned to their loyalty. Louis was restored, and Lothair was sent into Italian exile.

The final crisis of the reign came in 838. Louis, by then reconciled with his son Charles the Bald and with his younger son Louis the German, planned to give Charles Aquitaine and to give Louis, who had never received a sub-kingdom, the whole of the East Frankish realm. In June 840, while Louis was suppressing a revolt in Brittany, Pepin II of Aquitaine, the son of his eldest son, invaded the emperor’s lands. Louis the Pious died at Ingelheim on 20 June 840, and the empire passed to his three surviving sons, in the arrangements he had tried to dictate from his deathbed.

The Battle of Fontenoy and the road to Verdun

The emperor’s death did not bring peace. The three brothers — Lothair I, Louis the German, and Charles the Bald — immediately disputed the inheritance. Lothair, as the senior, claimed the whole empire. Louis the German, who had spent the previous year at his father’s side, claimed the East Frankish lands east of the Rhine. Charles the Bald, the youngest, claimed the West Frankish lands west of the Rhône and the Saône. The dispute could not be settled by negotiation. On 25 June 841, the brothers met in battle at Fontenoy-en-Puisaye, in present-day Burgundy. The army of Charles the Bald and Louis the German defeated the army of Lothair in a bloody engagement that contemporaries described as the worst slaughter of Franks since the wars of antiquity.

The battle did not settle the question. The brothers returned to their camps, and the war continued for two more years. Lothair’s position was weakened by his failure at Fontenoy and by rebellion in his Italian lands, but he still held the imperial title and the rich middle kingdom that stretched from the Low Countries to Italy. In February 842, Charles the Bald and Louis the German met at Strasbourg and swore the famous Strasbourg Oaths, each in the language of the other’s army, against Lothair. The oaths, preserved by the historian Nithard, are among the most important documents of early medieval Europe: the earliest surviving text in Old French and one of the earliest in Old High German.

The terms of the treaty

The Treaty of Verdun was concluded in August 843, probably on 10 August. The negotiations were led by Lothair’s chancellor, the future archbishop Drogo of Metz, and his West Frankish counterpart. The terms, as recorded in a series of documents preserved in the chancery archives, divided the empire into three kingdoms.

Lothair I, the senior, received the middle kingdom: a long, narrow strip running from the Low Countries through Lorraine, Alsace, Burgundy, and Provence into Italy. He also received the imperial title and the city of Aachen, where Charlemagne had been buried. The middle kingdom was the wealthiest per capita of the three, but it was also the most vulnerable, lacking the natural frontiers that protected the eastern and western realms. Its capital moved with the king, but its principal cities were Aachen, Prüm, and Lyon.

Louis the German received the East Frankish lands: the Rhineland, Saxony, Bavaria, and the marches of Thuringia, Pannonia, and the Slavic frontier. The kingdom corresponded broadly to the areas of Germanic speech and formed the core of what would become the Holy Roman Empire and modern Germany.

Charles the Bald received the West Frankish lands: the Île-de-France, Neustria, Aquitaine, Septimania, and the Spanish March. The kingdom corresponded broadly to the Romance-speaking areas of the old Frankish realm and formed the core of what would become medieval and modern France.

The treaty was, in effect, a recognition of the linguistic, cultural, and political differences that had been developing within the Carolingian Empire for generations. The East was German-speaking, the West was Romance-speaking, and the middle kingdom was a transitional zone where the two languages and cultures met. The treaty accepted these differences and drew the political boundaries along them. The result was a durable political geography that, in broad outline, persisted for a thousand years.

The middle kingdom and the Treaty of Meerssen

Lothair I’s middle kingdom was the first to fail. Lothair, exhausted by the wars of his reign, abdicated in 855 and retired to the monastery of Prüm, where he died two days later. His kingdom was divided among his three sons: the eldest, Louis II, received Italy and the imperial title; the second, Lothair II, received the northern part of the middle kingdom, which became known as Lotharingia; the youngest, Charles, received Provence. Charles died without heirs in 863, and his lands were divided between his brothers.

Lothair II’s Lotharingia was contested by both his uncles. In 867 Lothair II acknowledged Louis the German as his heir, and in 870, after Lothair’s death, Louis and Charles the Bald divided Lotharingia between them by the Treaty of Meerssen. The treaty gave most of Lotharingia — including Aachen, Metz, and the Rhineland — to Louis the German, and the lower parts of modern Lorraine and Burgundy to Charles the Bald. The middle kingdom had effectively ceased to exist.

The end of the Carolingian dynasty

The treaty of Verdun did not, of itself, end the Carolingian dynasty. The line continued in the East Frankish kingdom until 911, in the West Frankish kingdom until 987, and in Italy intermittently until the late ninth century. But the political unity of the empire was broken beyond repair. The successors of Charlemagne fought one another for possession of Lotharingia, the Spanish March, Italy, and the imperial title. The struggle weakened the dynasty and strengthened the great aristocratic families who would replace it.

In the West, the last Carolingian king was Louis V, who died in 987. He was succeeded by Hugh Capet, count of Paris and duke of the Franks, who founded the Capetian dynasty that would rule France until 1792. In the East, the last Carolingian king of Germany was Louis the Child, who died in 911. He was succeeded by Conrad of Franconia, the first non-Carolingian East Frankish king. The Holy Roman Empire, the institution that would in theory reunite Charlemagne’s realm, was established in 962 when Otto I, the Saxon king, was crowned emperor by Pope John XII.

The Carolingian Empire did not survive. The Holy Roman Empire, the Kingdom of France, the German kingdom, and the long struggle between them all date from the partition of Verdun.

The legacy of Verdun

The Treaty of Verdun has been called, with some justice, the birth certificate of Europe. It is the first document to recognize, in the political order, the threefold division of the Latin West into Romance, Germanic, and intermediate zones. The boundary it drew in 843 has been adjusted, redrawn, fought over, and contested ever since. The Franco-German border, the Belgian-Dutch-German border, the Swiss-German border, and the Italian-Austrian border all run, in their broad outlines, along the line that the Carolingians’ grandsons drew at Verdun.

Yet the treaty was not only a division. It was also the first step in the construction of the European kingdoms that would dominate the Middle Ages. The kingdom of Charles the Bald became, with the accession of the Capetians, the kingdom of France. The kingdom of Louis the German became, with the accession of the Ottonians, the Holy Roman Empire. The middle kingdom, in its successive Lotharingian, Burgundian, and Provençal forms, became the contested borderland that the modern states of the Low Countries, Lorraine, Switzerland, and northern Italy inherited.

The treaty was also, like all the great political settlements of the Middle Ages, an event with both a contemporary meaning and a long historical resonance. To the men of 843, it was the end of a civil war and the partition of a great inheritance. To later generations, it was the foundational act of the European order. Both readings are correct.