Carloman I

Carloman I (28 June 751 – 4 December 771), German Karlmann, Karlomann, was king of the Franks from 768 until his death in 771. He was the second surviving son of Pepin the Short and Bertrada of Laon and was a younger brother of Charlemagne. His death allowed Charlemagne to take all of Francia.

Source: Wikipedia — https://en.wikipedia.org/wiki/Carloman_I