Cors Jansz van der Morsch and Catrijn Jansdr. van der Morsch are children of Catrijn Claesdr. An inheritance paper of Seger Huigens and Maritje Claesdr. shows larger family of siblings with patronymic "Claesz/Claesdr." (Groene Hart archieven protocollen Hazerswoude 1589-1601 date 13 April 1594)
It has been said that "Catrijn Claesdr." was first wife of Jan Lyclaesz (van der Morsch) but no conclusive connection has been found.
Jan Lyclaesz marr. Dieuwertje Sijmonsdr. children: Maritge,Bruijn, Dirck, Ocker.