Geoffroy was the son of Briant I de Châteaubriant but his mother is unknown. The date and place of his birth have not been found.
His wife is not known. They were married, but the date and place have not been found. Their only known child was Braint II (c1115-c1186).
| Attribute | Date | Description | Details | Source | Multimedia | Notes |
|---|---|---|---|---|---|---|
| Nobility Title | seigneur de Châteaubriant |