Guillaume was born about 1175, the son of unknown parents. The place is not known.
He died about 1215. The place is not known.
His wife was Constance de Pontchâteau, who he married in ABT 1206. The place has not been found. Their only known child was Olivier I (1206-1262).
| Event | Date | Details | Source | Multimedia | Notes |
|---|---|---|---|---|---|
| Birth | ABT 1175 |
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| Death | ABT 1215 |
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