Alternate date of death: 17 Aug 754.
Einhard names "Karlomannum…et Pippinum atque Grifonem" as the three sons of "Karlus maior domus" when recording the latter's death. The Genealogica Arnulfi Comitis names (in order) "Pipinum, Karlomannum, Griphonem et Bernardum" sons of "Karolus senior…ex regina". "Karlomanni filii eius" subscribed the charter dated 1 Jan 722 under which "Karolus maiorum domus filius Pippini quondam" donated property "castrum…Fethna sitam in pago Nifterlaco" to the monastery "infra muros Traiecto castro".
He succeeded his father as maior domus, jointly with his brother Pépin. They deprived their half-brother Grifo of his inheritance, and defeated him after he rebelled against them. In the division of territories agreed with his brother, Carloman governed Austrasia, Alemannia, Thuringia and northern Alsace. The brothers were faced with revolts in Frisia, Bavaria, Alemannia and Aquitaine. As a symbolic assertion of their authority, they nominated Childeric III as [Merovingian] king in 743. Einhard records that "Karlomannus" was in Saxony at "castrum Hohseoburg" and there accepted the surrender of "Theodericum Saxonem illius loci primarium" in 743. "Childerichus rex Francorum" with "Karolomanno maiores domus, rectori palatio nostro" confirmed donations to the monastery of Stablo and Malmedy by charter dated Jul 744. In 745, Carloman's brother Pépin appropriated the province of Alemannia for himself. Carloman reasserted his authority with an expedition against the Alemans in 746, massacring the leaders who had betrayed him to his brother. This triggered the defection of his other supporters, and Carloman relinquished power. The Chronicon Sancti Medardi Suessionensis records that “Carlomannus frater Pippini junioris” became a monk in 745 and that “Pippinus junior parvus frater eius” obtained the whole of “Principatum Francorum”.
The Royal Frankish Annals record that, after 15 Aug 747, he left for Rome, where he built the monastery of St Sylvester on Monte Soracte before moving to the monastery of St Benedict at Monte Cassino where he became a monk. He returned to France in 753 to oppose the request by Pope Stephen III (II) for Frankish help against the Lombards. The Annales Moselleni record the death in 754 of "Karlamannus".
http://fmg.ac/Projects/MedLands/FRANKSMaiordomi.htm#_ftnref204
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