'My Aunt [Cassandra] looked them over and burnt the greater part, (as she told me), 2 or 3 years before her own death -- She left, or gave some as legacies to the Nieces -- but of those I have seen, several had portions cut out -- ' (Aunt Jane, pp. 9- 10).6
Frank's eighth daughter, Catherine Anne (who became Catherine Hubbard) saw a group of letters Jane had written to Cassandra about the trauma Jane had known when in December 1802 she accepted and then hastily rejected a proposal of marriage from the wealthy younger brother of the Bigg sisters. These Cassandra destroyed.
Fanny Austen Knight received thirty, not six letters from her aunt.
A collection of letters and other documents by (among others) Jane 's mother and father, James, Edward, Henry, Frank, Charles, Eliza and Philadelphia Walker (a first cousin to them all), and Jane Leigh-Perrot, frequently end with the command 'Burn this!' or 'Pray do not neglect burning this'.
It was not Jane but Cassandra who burnt 'the greater part' of Jane's letters, and she only committed them to the fire when in 1842 she understood her own death could not be far off.
Jane's letters to Eliza and Henry and hers to them were left in Henry's hands, and they have not survived.
However, Frank, throughout a long mobile life, carefully preserved Jane's letters to his first wife, Mary Gibson, and her packets of letters to himself and to Martha Lloyd (who became his second wife). It was Frank's youngest daughter, Fanny-Sophia, who destroyed these and she did so after her father's death (Family Record, p. 252). She acted without consulting anyone beforehand because by that time mores had changed and other of Frank's children and grandchildren would have objected.
Happily Philadelphia Walker had no direct descendents who felt their reputations or self-esteem put at risk by the existence of Eliza's letters to her, and she lived long enough so that upon her death these letters fell into the hands of someone disinterested enough to save them, though in a somewhat mutilated state.
A record of Jane Austen's great-grandmother, Elizabeth Weller Austen's steady courage, which enabled Jane's branch of the family to maintain the status of gentleman and amass wealth and prestige, survives in a seventeenth century manuscript because several generations of Austens who descended from her second oldest son, the attorney, Francis Austen of Sevenoaks, preserved it (Austen Papers, p. 2).