Guillaume was the son of unknown parents. The date and place of his birth have not been found.
His wife was Mathilde d'Aigneaux, who he married in BEF 1232. The place has not been found. They had no known children.
| Attribute | Date | Description | Details | Source | Multimedia | Notes |
|---|---|---|---|---|---|---|
| Nobility Title | seigneur de Lantheuil |