Guillaume was born about 1290, the son of unknown parents. The place is not known.
His wife was Margareta van Loon. They were married, but the date and place have not been found. They had no known children.
| Event | Date | Details | Source | Multimedia | Notes |
|---|---|---|---|---|---|
| Birth | ABT 1290 |
|
Note 1
Son of Johan van Dammartin and Alix de Walcourt, comtesse de Duras