In my first post about Johannes Ambuul, I mentioned there were three sons named Willem. After the first Willem died, the next son was also named Willem, and then again for the third after the second Willem died. This custom was in line with the traditional Dutch practice of baby naming at that time. It usually followed this pattern:
–First-born son is named after paternal grandfather
–First-born daughter is named after maternal grandmother
–Second son is named after maternal grandfather
–Second son is named after paternal grandmother
For the rest of the lot, children were many times named after uncles and aunts.
However, if a son died before his next brother was born, the younger brother was usually given the same name, and it was the same for a daughter. If the father died before his son was born, the son was usually named after him, the same with the mother.
I have not fully researched Johannes Ambuul’s family line, but what I have found on a couple of other private family websites (all data needs to be confirmed) is his father’s name was Willem. I’m going to guess that is correct.