The Rulers of Normandie from Rollo in 911 to William who became King of England used the titles of Jarl and then Dux (Duke). This project includes the main line with all their various partners and children.
The project might be extended to include a few more generations as well.
This project is a sub-project of Norman Families of Normandy and England.
Ambiguity and Discrepancies
If there is doubt about relationships, we normally rely on the Medieval Lands database. This is the most well-researced source we have, referring to primary texts only, presenting discrepancies, and with little interpretation.