The patronymic Janszoon means 'son of Jan,' or 'son of Johannes' (Janszoon in Dutch). In the early seventeenth century, this was in some dialects probably pronounced the same as Jansen, a name equivalent to Johnson in English. Surnames were usually not used and children were simply named for their father's given name. In areas where not many people lived, but also in towns and cities, he would simply be given the name Willem Jansz; thus, all that is known about him is that his father's name was Johannes or Jan. As in many countries, genealogical and historical research in the Netherlands can be difficult for this reason. See Note on 17th Century Dutch names. Project Gutenberg of Australia. 31 July 2005.
