Robert succeeded his brother, Charles III of Alençon, in 1361 as Count of Perche in Normandy, after Charles renounced his counties[2] and became a Dominican friar, choosing Couvent des Jacobins de la rue Saint-Jacques in Paris.

[3][Note 1] Philip, the eldest of Charles's younger brothers, had become bishop of Beauvais in 1356,[2] and so their mother obtained permission from King John II of France to divide the counties between the remaining brothers, Peter and Robert.

[4] Robert established his court at Nogent-le-Rotrou, a fortified town about 10 miles (16 km) south of Bellême and the county capital of Perche.

Upon Robert's death in 1377, his title of Count of Perche passed to his elder brother, Peter II, Count of Alençon (French: Pierre d'Alençon), merging the counties of Alençon and Perche.

[5] Robert's brother and heir, Peter II, Count of Alençon, was portrayed by actor Ben Affleck in the same film.