It is interesting that at the beginning of his career Charles Martel had to raise on Clotaire IV as king but by  there was no need to appoint a successor to Theuderic IV  Clearly his reign completely changed the dynamics of rulership in Francia the hallowed Merovingian line was necessary to legitimise his authority early on but his fighting on behalf of the nation and Christendom apparently changed this he had legitimised his own rule himself and no king was needed  His sons may have feared that they had not yet proved themselves when they appointed Childeric III in   Pepins assumption of the title of king in  was probably an attempt to make the power won by he and his ancestors perminent for his descendants