During his absence, Regent Christine had gained control of the fortresses granted to Thomas as part of the settlement of the Piedmontese Civil War (legally, these reverted to ducal control when the Duke came of age), which under Piedmontese law Charles Emmanuel did in 1648, though his mother remained in control of the government; Christine, accompanied by her son and part of the ducal army, entered Ivrea and dismissed Thomas' personal garrison; she appointed Thomas instead as governor or Asti and Alba, positions which sweetened the blow but were entirely under ducal control, not guaranteed by treaty. When he returned to Piedmont, Thomas had no choice but to accept the fait accompli, and soon after this he went to live in Paris.