The generally accepted view has been1 that Gerrit van Wijk was the son of Arie van Wijk and Cornelia Helms; that he was three times married, to Elisabeth Vivier, to Maria Provo and to Maria Magdalena Eekhof; that he produced nineteen children between 1723 and 1764.
My investigation of the extant church registers, wills, estate accounts and estate inventories has made it plain to me that there were, in fact, two men named Gerrit van Wijk, neither of them the son of Arie van Wijk and Cornelia Helms.
1
Gerrit, the son of Arij van Wijk and Cornelia Helmes was baptised in Stellenbosch on 14th December 1707, his godparents having been Adam Tas and Elisabeth van Brakel, and, in all probability, buried2 in the same place sometime before 12th August 1708.
His mother, Cornelia Helmes made two wills. The first was made in April 1713,3 a joint will with his father, Arij van Wijk, probably at that time on his death bed, and the second made in May 1720, a joint will with her third husband4, Jacob Coetser, shortly before she herself died. In both wills her children by Arij van Wijk are stated to have been 8 in number and are individually named; in neither will does a child named Gerrit appear.
When Willem van Wijk, called the elder (d'oude) died in 1772 he left no will and no wife or descendants. The account of his estate was drawn up by the officials of the Weeskamer. His brothers and sisters, whole and half, or their children, are carefully named5. It is clear that he was the son of Arij van Wijk and Cornelia Helmes, and once again there is no mention of a brother named Gerrit.
2
In the Inventory drawn up on 16th August 1730 after the death of Elisabeth Vivier, her husband is named as Gerrit van Wijk, but in the joint will made by him with his second wife6, Maria Provo, he is named as Gerrit Willemsz: van wijk. This will was presented to the Weeskamer on 8th January 1738.
And in the Instrument drawn up by Maria Provo upon her subsequent marriage with Gerrit van Schalkwijk, dated 21st October 17407, her late husband is again named as Gerrit Willemsz: van Wijk.
This would imply that the Gerrit van Wijk who was married firstly to Elisabeth Vivier and subsequently to Maria Provo, had died before January 1738 and was the son of someone called Willem (see my notes on his probable parentage).
3
Gerrit van Wijk and Maria Magdalena Eekhof were married at Drakenstein8 on 2nd November 1738, when Gerrit the husband of Elisabeth Vivier and Maria Provo had been dead almost a year.
No mention is made in the marriage register of his or her marital status (ie. jongman/bachelor or weduwenaar/widower) as was usual at that time and on that page, before and after this entry, but the reason for this becomes plain when one sees that their eldest child was baptised at the same service8 at which his parents were married (it was normal to baptise children and marry couples at the end of a normal Sunday church service).
In 1775 Gerrit and Maria Magdalena drew up a will in which they make special provision for their sons Arie Willems and Gerrit Matthij9. In this will they are named as Gerrit van Wijk Ariisz: en Maria Magdalena Eijkhoff. This will was filed in November 1776, presumably after the death of Maria Magdalena.
When Gerrit van Wijk died intestate in 1787, the accounts drawn up at that time name him as 'Gerrit van Wijk Arrysz:' and list his eleven children, starting with Ary Willemsz van Wijk and including Gerrit Matthijs van Wijk, mentioned in the will above.
When Willem van Wijk died intestate in 1774, his estate accounts10 describe him as 'Willem van Wijk Arijsz:'. He apparently left no wife or children since his estate is divided amongst his brothers and sisters, whole and half, first among whom is Gerrit van Wijk Arijsz:. The names of his brothers and sisters make it plain that this group of Van Wijks are the children of Arij van Wijk Willemsz: and Antonetta Campher.
http://www.ballfamilyrecords.co.uk/notes/VanWijk_Gerrit.htm