I'm aware of the eccentricity of Dutch naming conventions prior to the Napoleonic occupation. I traced another family back to where the eight children had six different surnames, four being derivatives of the parents' first names. (Lars->Larsdotter, Berend->Berendson, etc.) I also knew of the tendency in that period to adopt surnames that had to do with something local (Updyke, Rothuis, Bloemendal, Grotenhuis) or occupation. Makes genealogy research interesting, doesn't it?