Hi Bart:

Found two mentions of a Jan Pietersz Pronck.  A brother of Maarten? 

ORA Rijnsaterwoude 11/140 verso (Scan 155) in July 1716:

https://www.familysearch.org/ark:/61903/3:1:3QHV-B3RT-T9NK?i=154&cat=179884

ORA Rijnsaterwoude 12/157 (Scan 361) in January 1720:

https://www.familysearch.org/ark:/61903/3:1:3QHV-13RT-T9C4?i=360&cat=179884

Could very well be. Unfortunately these are 'Transportregisters' dealing with the transfer of real estate, buying/selling, loans, mortgages etc. I looked at the documents, and they do not seem te reveal any family connections, but I must say I didn't read all of it.

Hi Bart:

As you probably surmised, the patronymic is the only clue.  Unfortunately, the (RK) church registers in the Rijnsaterwoude area are sparse for the time period (1640-1730) that would solve the riddle.  That's what I have found so far.  That's why I have been searching through court documents as an alternative route.

Regards, Steve

I'll just put in my two cents:  I also came across Jan Pietersz Pronck in a Weesboek from Alkemade < LINK > . September 1702 that was, and it's about a guardianship. It won't help you, because I'm pretty sure this is about Jan's mother and father in law. But I also think he will be Maerten's brother.

And talking about the Weeskamer: Rijnsaterwoude's weesboeken from 1679-1685 and then from 1712 on are available through Family Search. I have some notes, but no Proncks in them. That doesn't say much, because I was looking for other families. Same goes for ONA Rijnsaterwoude, from which there are deeds in the years 1671-1688.

Regards, Frans