The Rise of Charlemagne and How He Became King of the Franks

On October 9, 768, a young man named Charles stepped into a world about to change forever. His father, Pepin the Short, was dead. The throne of the Franks, a kingdom stretching across much of Western Europe, now belonged to two brothers who barely trusted each other. One was Charlemagne. The other was Carloman.

They stood side by side as kings, but they weren’t exactly united. The kingdom was split, and so were they. Their father’s death had left behind pressure, ambition, and a fragile peace that would not last long.

Few could have guessed that this moment marked the beginning of one of the most powerful reigns in medieval Europe. Before Charlemagne became emperor, before the conquests and the reforms, he was just one half of a divided kingdom.

The Carolingian House and the Merovingian Legacy

Charlemagne was born into a family accustomed to wielding power. His father, Pepin the Short, wore the crown, and his mother, Bertrada of Laon, knew how to move through the world of politics. His grandfather, Charles Martel, had ruled before them, not as king but as the man every king depended on.

For generations, the Merovingians had been kings in name, but the real authority lay with the mayor of the palace, a title that once meant administrator but had grown into something far greater. By the early eighth century, the king led ceremonies and blessed new laws, while the mayor raised armies, collected taxes, and decided who kept their lands.

Charles Martel mastered that role. He fought and won battles that secured Frankish borders, rewarding his soldiers and bishops with estates taken from defeated foes. Land was the key to loyalty, and through it, Martel built a network of men who owed him everything. He ruled through the Merovingian kings but not beneath them. Everyone at court knew who truly made the decisions.

When Martel died in 741, his sons, Pepin and Carloman, inherited the system he had built. They ruled together in the name of a powerless Merovingian king. But Pepin was not content to stand behind the throne forever. He asked Pope Zachary who should bear the title of king? The man who holds power or the man who only bears the title? The pope’s answer gave Pepin what he wanted: the blessing to make it official.

In 751, the last Merovingian king, Childeric III, was deposed. His long hair, the ancient symbol of royal blood, was cut away in public before he was sent to live out his days in a monastery. Pepin was chosen by the Frankish nobles, anointed with holy oil, and crowned king.

Three years later, in 754, Pope Stephen crossed the Alps to meet him at Saint Denis. He anointed Pepin again, this time in a ceremony that also included Pepin’s two sons, Charles and Carloman. The bond between the Franks and Rome was now sealed in holy oil. Pepin soon proved his worth to the Church by marching into Italy, defeating the Lombards, and granting land to the papacy. Those lands formed the Papal States, and the alliance between throne and altar would shape European power for centuries to come.

Bertrada of Laon

Pepin’s marriage to Bertrada of Laon helped strengthen the Carolingian hold on power. She came from an influential noble family in northern Francia and had a sharp sense for politics that would later prove crucial to her sons. 

Their union was initially considered unorthodox, but the Church took time to recognize it. However, together they built a dynasty that combined military strength with careful diplomacy.

Bertrada gave Pepin three children: Charles, Carloman, and their sister Gisela. Chronicles describe her as intelligent, persuasive, and capable of steadying the volatile world around her husband. 

A Kingdom Split in Two

By the time Pepin died in 768, he had reshaped the Frankish kingdom. The empire he built passed to his two sons. Charles, who would later be called Charlemagne, was already an experienced commander. Carloman, his younger brother, was quieter and less proven but carried equal authority by law and anointing. Their mother, Bertrada of Laon, stood between them, hoping to hold the peace she and her husband had worked so hard to create.

The coronations took place on the same day, 9 October. Charles was crowned at Noyon, and Carloman at Soissons. These two cities lay only about sixty miles apart, yet the distance between the brothers was far greater. They inherited a kingdom that was strong but complicated, a patchwork of loyalties and local power that depended on personal presence. 

Following Frankish custom, the realm was split. Carloman received the central and southern territories, including Burgundy, Provence, and Alemannia. Charles ruled the western and northern parts, including Neustria, Flanders, and a large portion of Aquitaine. The division was not a neat little package, far from it. Church lands and noble estates crossed both spheres, and so did family loyalties. It was hardly the start of a peaceful reign.

Carloman had the wealthier heartlands. Charles had the stronger networks among the army and the frontier nobles. Those who had fought with Pepin in Saxony and Aquitaine already looked to him for leadership. Both men held the same title, but from the beginning, Charles carried the momentum.

The Unfinished War in Aquitaine

The tension between them surfaced almost immediately. When Pepin died, his army was still putting down a long-running rebellion in Aquitaine, a region that had resisted Frankish control for decades.

Aquitaine had once been ruled by Duke Waiofar, a powerful local leader who treated his duchy as if it were an independent kingdom. Pepin had spent years trying to bring him to heel. Waiofar’s assassination in 768, just before Pepin’s own death, left the region unstable. His nephew Hunald, sometimes called Hunald II, took up the cause. He rallied Waiofar’s remaining followers and attacked Frankish garrisons, determined to restore Aquitaine’s freedom.

Pepin’s death gave Hunald the opening he needed. A divided Francia might be easier to shake off. Both new kings were expected to finish what their father had started. Charles gathered his forces and called for Carloman to join him. Carloman refused.

The reason was never written down, but pride and rivalry likely drove it. Carloman did not want to serve under his brother’s command or see Charles win prestige among the nobles. His absence spoke volumes. Charles pressed on alone, marched south, and crushed the rebellion. Hunald fled to Gascony, where Duke Lupus handed him over to the Franks to avoid war.

Rival Courts and Bertrada’s Balancing Act

While Charles’s reputation grew, Carloman’s court became more isolated. He surrounded himself with older advisers and churchmen who preferred caution to risk. His brother’s court was full of soldiers, administrators, and ambitious nobles who saw their future in expansion, not compromise.

Bertrada moved between them, trying to keep the kingdom from tearing itself apart. She understood that diplomacy could buy time, even if it could not repair trust. In 770, she set out on a mission to Italy, arranging a marriage between Charles and Desiderius’s daughter, a Lombard princess. The match was meant to secure peace in the south and balance the brothers’ power by aligning one branch of the family with Italy and the other with the central Frankish lands.

The plan did not go well. Pope Stephen III condemned the alliance, warning that any bond with the Lombards would endanger Rome. Carloman’s advisers mocked it and accused Bertrada of favoring Charles. Within a year, Charles ended the marriage and sent the princess home. It was a public humiliation for the Lombards and a message to everyone else. Charles would not be bound by arrangements that no longer suited him.

The Final Strain

By 771, the two courts were acting like rival kingdoms. Relations had broken down, and reports of a looming war reached Rome. Bertrada was exhausted by her sons’ feud, and the papacy began to hedge its bets, uncertain which side to support if conflict came.

Then, fate intervened. Carloman fell ill and died suddenly in December 771 at his villa in Samoussy. He was only twenty. His widow, Gerberga, fled with their two young sons to Italy, seeking protection at the Lombard court. Charles wasted no time. He seized his brother’s territories, ignored his nephews’ claims, and united the Frankish kingdom under his sole rule.

The joint kingship that began on October 9, 768, had lasted barely three years. Carloman’s death removed the only obstacle to Charles’s full control. From this point on, Charlemagne ruled alone. The experience of those early years taught him that power depended on presence, strength, and speed. He had watched his brother hesitate and lose everything. He would not make the same mistake.