However, Marlborough's hopes of founding a great dynasty of his own reposed in his eldest and only surviving son, John, who, since his father's elevation, had borne the courtesy title of Marquess of Blandford.
Marlboroughs håb om at grundlægge et stort dynasti hvilede på hans ældste og eneste overlevende søn John, som efter sin fars ophøjelse havde båret titlen Markis af Blandford.