Baroness Maria Cornelia van Heeckeren van Wassenaer Countess von Bentinck (1855–1912) Parents Isabella Antoinette, Barones Sloet van Toutenburg Jacob Dirk Carel van Heeckeren van Wassenaer Children Frederick George Unico Williams Bentinck William Frederick Charles Henry Bentinck, 7th Graf Bentinck Mechtild von Bentinck Countess Isabella von Bentinck Siblings Baron Rudolf Fredrik de Heeckeren de Wassenaer Partners Wilhelm Aldenburg-Bentinck, 6th Graf Bentinck
