Isaac Witsenhuijsen was a son of Abraham Witsenhuijsen and Clara Waterman. He married on 20 October 1915 in Amsterdam to the 28-year old Vrouwtje Velleman, daughter of Levie Velleman and Aaltje Zomerplaag. Vrouwtje Velleman however passed away on 21 March 1930 and Isaac Witsenhuijsen marrieg again on 31 December 1930 to Leentje Tonninge, daughter of Mozes Tonninge and Rijntje Metz.
From his first …