 It was only in areas like Neustria, where Carolingian opposition historically existed, that Charles knew he would face criticism if he usurped the throne.Therefore, until his death, Charles ruled as "Princeps" or Prince, officially gaining the title with his uncontested leadership with the acquisition of Provence in 737.This meant that the issue of kingship remained ever present for his successors who would have to work further to establish themselves as royal.