Along with his brother Charles, Carloman was anointed as king by Pope Stephen III in 754. After Pepin's death in 768 AD, Carloman and Charles divided the kingdom between them, with Carloman taking the eastern portion, Austrasia. There was considerable tension between the brothers, which may be the reason why, at Carloman's death, his wife Gerberga fled with her sons to the court of Desiderius, king of the Lombards. Because some sources state that Gerberga was Desiderius' daughter, it is difficult to judge the level of fraternal tension. Chronicles more sympathetic to Charles imply that he was bemused by Gerberga's action. Upon Carloman's death, his kingdom was absorbed into Charles', who then distributed portions to his own sons.
In 768Pippin divided his dominions between his two sons, and on his death soon afterwards Charles became the ruler of the northern portion of the Frankish kingdom, and was crowned at Noyon on the 9th of October 768.
Carloman's widow Gerberga had fled to the protection of the Lombard king, who espoused her cause and requested the new pope, Adrian I., to recognize her two sons as the lawful Frankish kings.
According to Berte aus grans pies, in the 13th-century remaniement of the Brabantine trouvere Adenes le Rois, Charlemagne was the son of Pippin and of Berte, the daughter of Flore and Blanchefleur, king and queen of Hungary.
There was considerable tension between the brothers, which may be the reason why, at Carloman's death, his wife Gerberga fled with her sons to the court of Desiderius, king of the Lombards.