Rotrou I "le Grand" de Châteaudun, comte du Perche - Birthplace RE 11th-c.

For what its worth ... or not –

Suggested birthplace strand change: Mortagne-au-Perche, Duché de Normandie

1. Orne is a"départment" designation. Départments didn't exist until the French Revolution was underway.
https://en.wikipedia.org/wiki/Departments_of_France#History '''départments of France.

2. In 1075, Normandy was an autonomous duchy. The region folded into French control many years after the Frankish empire collapsed. After William the Conqueror and his leaders went to England. Normandy was ravaged by battles for control of it. It took a long time before France, as a country, won the region for good.
https://en.wikipedia.org/wiki/History_of_Normandy#Ducal_Normandy_(1... Duché de Normandie