Biography
Willem Jansz Knoppert was born circa 1605 in Zwolle, Overijssel, Netherlands to Jan Knoppert (bef1581-bef1628) and Mechtelina Splijthoff (bef1581) . He married Elisabeth van de Gelder (bef1618) 1 May 1635 in Utrecht, Utrecht, Netherlands.
Children
| Name | Birth | Death | Joined with |
| Jan Willemsz Knoppert (1636-bef1712) | 1636 | 1712 | Marijke Jansdr van Velpen (bef1646-aft1711) |