Gerrit was born about 1300, the son of Gerrit II van Heemskerck but his mother is unknown. The place is not known.
His wife was Margaretha van Cralingen. They were married, but the date and place have not been found. Their two known children were Clementia (c1400->1466) and Agnes (c1335-c1400).
| Event | Date | Details | Source | Multimedia | Notes |
|---|---|---|---|---|---|
| Birth | ABT 1300 |
|
| Attribute | Date | Description | Details | Source | Multimedia | Notes |
|---|---|---|---|---|---|---|
| Nobility Title | heer van Heemskerk, Oosthuizen, Luttich en Dreysitter |