Answer
Childeric III, the last Merovingian king, was replaced by Pepin the Short as the figurehead King of the Franks. Pepin, the father of Charlemagne, effectively wielded the real power as the Mayor of the Palace and sought legitimacy by allying with the Pope and deposing Childeric III in 751. This marked the beginning of the Carolingian dynasty, which would shape the political landscape of Western Europe for centuries