Catholic records were kept in Latin, while civil registration records are kept in Dutch (or French, depending on the time). But Catholic families often recorded the Latin version of the name as the official version with the civil authorities as well. Latin names often ended in -us (for men) or -a (for women).
So a person who was called Petrus Josephus in the official records, may well have been called Piet in his every-day life. Here are some other names with their Dutch given names.
Men: Johannes (Jan), Josephus (Josef), Theodorus (Dirk, Theo), Gerhardus (Gerrit, Geert, Gert), Stephanus (Steven, Stefan), Hendrikus (Henk, Hendrik), Adrianus (Ad, Adriaan, Aart, Janus).
Women: Catharina (Katrien, Kato, Toos), Johanna (Janna), Maria (Mia, Marie, Mietje, Riet), Adriana (Sjaan, Jaantje), Gertrudis (Geertruida, Trui), Magdalena (Lena), Margaretha (Margriet, Grietje, Greta).
Catholic families often gave their children two or even three first names, so if you see a string of names like Johannes Gerardus Theodorus, you can make a bet that the family was Catholic.
Thank you so much for you helpful advice and information. You have helped me so much with the Dutch relatives from the Albany area, who came from Gelderland, which by the way became a suburb of that same city in New York. Who knew! Now I do.
I have two questions. My grandmother had three first names, all ending in “a”. Her father was Jan, which I now learn was Johannes, like his father. Again, who knew! The question, in Albany they belonged to the Dutch Reformed Church. In fact Harmina, her name, was married there. To me that doesn’t seem likely for a Catholic family. Is it?
Also her name in the Dutch records was Harmina, but in the U S she went by Mary, always. On my German side a relative was Amalie, but can be found in various records as Mary. How likely is it that Harmina would use Mary as her given name in America?
Thank you so much for sharing your expertise with those working on their Dutch ancestors. I wish I could find the same help for others in my tree!
Carol
I’m wondering about myself, I have ancestors in New York and New Jersey in the 1650s who also belonged to the Dutch Reformed Church but had names such as Casparus and Cornelius, etc.
Cornelius is often an English translation of the Dutch Cornelis. Casparus is Latin for the Dutch name Casper. It would be unusual for a protestant to call himself that, except perhaps if he had studied Latin, like if he was a minister or doctor.