Since he became Count of Savoy at the age of nine, he required a regency. The uncles were, however granted compensation in return, receiving more properties within the County. When Thomas died in 1259, Cecile continued as regent in Savoy.
Under her regency, Philip and Peter continued their previous work of expanding the control and influence of the County of Savoy.
Boniface"s campaigns in Flanders and Piedmont were not successful. In September 1262, Rudolf of Geneva offered homage to cousin Boniface after yet another round of the war between Peter and their kin in Geneva.