Childebert III Adoptivus and Adoption
Frankish kings of Austriasia, 657-662
Childebert is usually reckoned to be the natural son of Grimoald I, the mayor of the palace of King Sigibert III of Austriasia (the region of present-day France around Metz), who adopted him, although another version of the story has the situation reversed. By the time of Sigibert the Merovingian dynasty was almost powerless, real power having shifted to the hereditary mayors of the palace. When Sigibert died in 657, Grimoald had the rightful heir, Dagobert, sent to Ireland "on pilgrimage," while he installed the boy Childebert as his puppet on the throne. This caused opposition among the nobles, however, which resulted in 662 in Grimoald's murder and Childebert's overthrow and probably his death as well.
Biographisch-Bibliographisches Kirchenlexikon. (Herzberg: Verlag Traugott Bautz, 2001). Also available at:  Schreiber, Karl-Heinz. "Childebert III. Der Adoptierte" Available at:  Ilaender, Christian. "Die Frühen Karolinger, die Ahnen Karls des Grossen." Available at: