I find it rather interesting how the name of FATHER JACOB KRUIZE morphed over time.  Notice how Jacob's father changes (the patronymic).  Dates given are death dates in the order of their respective deaths.

1806 - TRYNTJE - JAKOB KRUIZE

1833 - SYBOLD - JAKOB HINDERKS KRUISENGA & EISKE JAKOBS DAM

1847 - EGBERT - JAKOB KNELLIS KRUIZINGA & EISKE JAKOBS

1854 - HINDRIK - JAKOB KORNELLIS KRUIZINGA & EISKE JACOBS

1865 - DERK - JACOB CORNELIS KRUIZENGA & EISKE JACOBS

1865 - KLAAS - JAKOB KLAASSENS KRUIZENGA & EISKE JOHANNES

1867 - JACOB - JACOB JACOBS KRUIZINGA & EISKE JACOBS VAN DAM

1877 - STIJNTJE - JACOB JACOBS KRUIZINGA & EISKE JACOBS VAN DAM

Are there any hidden clues in the above?  Initially it may have been thought that Hindrik Jans was the father of Jacob.  Or at least he assumed the name.  But then through the period of 1847-1865, we see the name with various spellings of Cornelis, with the single exception written on the death certificate of son Klaas: but the name of Eiske is also botched leading me to believe that someone just did not know what they were talking about.

Then something interesting happens.  Suddenly we have unified names in the deaths of both Jacob Jacobs and Stijntje Jacobs.  Why was the patronymic "Jacobs" expressed in both places?  Why not "Cornelis"?  Interesting too that both these records utilize the FULL NAME of Eiske Jacobs van Dam.  Why??

Until recent times, the Dutch adhered to a particular naming convention for their children.  Even here in the States we see this practice continued up until the 20th century.  This naming convention makes the job of us genealogists a bit easier - if we are able to back trace through the generations.  Here is how it worked.

Son 1 - named after father's father
Son 2 - named after mother's father
Son 3 - named after father's paternal grandfather
Son 4 - named after mother's paternal grandfather
Son 5 - named for father's maternal grandfather
Son 6 - named for mother's maternal grandfather

Daughter 1 - named after mother's mother
Daughter 2 - named after father's mother
Daughter 3 - named after mother's maternal grandmother
Daughter 4 - named after father's maternal grandmother
Daughter 5 - named after mother's paternal grandmother
Daughter 6 - named after father's paternal grandmother

Of course there were exceptions to the above rules, but that was how it generally worked.

Now... taking the children of Jacob Cornelis Kruize and Eiske Jacobs Dam, we have listed:

Hindrik Jacobs - 1788-1854
Jacob Jacobs - 1790-1867
Tryntje Jacobs - 1792-1806
Derk Jacobs - 1793-1796
Derk Jacobs - 1796-1865
Egbert Jacobs - 1799-1847
Sibold Jacobs - 1801-1833
Klaas Jacobs - 1802-1865
Stijntje Jacobs - 1806-1877

Do the names fit?  Are there hidden secrets buried here??

We know from Jacob Kruize's death certificate that he was onegt (illegitimate) - meaning we do not know who his father was.  He was born out of wedlock.  I don't know if this was before or after the death of Trijntje Sybolt's first husband, Hindrik Jans.  But we can gather some information from discovered records.  Here are the knowns:

Jacob Kruize's maternal grandfather's name was Sibolt.
Jacob Kruize married Eiske Jacobs Dam.
Eiske's father was named Jacob Derks.
Eiske's paternal grandfather was named Derk.
Eiske's mother was named Styntje Egberts.
Eiske's maternal grandfather was named Egbert.

Here then are Jacob Cornelis Kruize and Eiske Jacobs Dam's children...

Hindrik Jacobs - Hindrik should be named for Jacob's father.  Apparently the first son was given the name of Jacob's "step" father Hindrik.  What should the name have been?  Given that Jacob's patronymic is Cornelis - Cornelis should be the name of the first son.  It is not. 

Jacob Jacobs - Jacob should be named for Eiske's father.  He was.

Tryntje Jacobs - Tryntje should be named for Eiske's mother.  She is not.  She is named for Jacob's mother.  Why? 

Derk Jacobs - Derk should be named for the father's paternal grandfather.  We don't know this information.  But apparently Derk was named for the mother's paternal grandfather.  This probably because of the flip-flop situation with Tryntje.  Or because they did not know themselves.

Egbert Jacobs - Egbert should be named after the father's maternal grandfather.  The mother's maternal grandfather's name was Egbert. 

Sibold jacobs - Sibold should be named after the father's paternal grandfather.  He was.

Klaas Jacobs - Klaas should be named after the mother's maternal grandfather.  Not certain who Klaas was named after.  But the mother's maternal grandfather's name was Egbert.

Stijntje Jacobs - Stijntje should be named after the father's mother.  She was not.  She was named after the mother's mother.

So what we have is not typical.

And there may be clues here. 

HINDRIK JACOBS - JACOB
JACOB JACOBS - EISKE
TRYNTJE JACOBS - JACOB
DERK JACOBS - EISKE
EGBERT JACOBS - EISKE
SIBOLD JACOBS - JACOB
KLAAS JACOBS - UNK
STINTJE JACOBS - EISKE

And Jacob's patronymic Cornelis - does this hold a clue?  Why wasn't jacob's firstborn named Cornelis? 

More information pending as I search for answers.

On the 1813 wedding registration of Jacob Jacobs, we find the name of Jacob Cornelis Kruize.  Normally, since Jacob died in 1822, we find him listed as "overleden" or deceased.  In this instance, Jacob is listed as being present - as is his wife Eiske Jacobs Dam.  On the document Eiske's signature is given but not Jacob's.  Sadly, it appears that Jacob was unable to write his name.  This would have been a great piece of Kruizenga history.  But we do have quite a collection of family members in addition to the mother: elder brother Hindrik Jacobs and uncles (mother's side) Egbert and Derk Dam. 

Today I was searching for an earlier civil record event that might shed some light on our elusive Jacob Cornelis ancestor.  I found the wedding record for Jacob Jacobs Kruize and his bride Ida Jans Kat which took place on 5 Sept 1813 in 't Zandt, Groningen.  Besides mentioning Jakobs Kornelis Kruize by name, Jacob Jacobs' uncles (mother's side) Egbert and Derk Dam and his older brother Hindrik signed the document (see below).