Janszoon
Janszoon usually abbreviated to Jansz was a Dutch patronym ("son of Jan"). While Janse, Janssens, and especially Jansen and Janssen, are very common surnames derived from this patronym, the form Jansz is quite rare and Janszoon itself does not exist in the Netherlands. People with this name or its variants include: As a patronym. Since "Jan" was the most common given name in the Netherlands for many centuries, the patronym was exceedingly common. To name a few: