a. The wife of a peer takes her husband’s style.
That is, she is Baroness, Viscountess, Marchioness, etc. In cataloguing, say Brassey, Annie (Allnutt), Baroness; not Brassey, Annie (Allnutt), Lady.
b. The wife of a knight or baronet is Lady. Whether this title precedes or follows her forename depends upon whether she had a title before her marriage.
That is, if Lady Mary Smith marries Sir John Brown (either knight or baronet), she is Lady Mary Brown, also if Hon. Mary Smith marries Sir John Brown (knight or baronet) she is Lady Mary Brown; but if Miss Mary Smith marries Sir John Brown (knight or baronet), she becomes Mary, Lady Brown.
c. A maid of honor retains her Hon. after marriage, unless, of course, it is merged into a higher title.
Thus, if she marries a baronet she is the Honble Lady Brown, if a peer the Lady So and So, in either case as though she had been a peer’s daughter.
d. The wife of an earl’s (or higher peer’s) younger son is never the Honble Lady; if she used the Lady before marriage in her own right she does not, of course, add anything by such marriage, but the wife of a younger son of a lower peer than an earl is Honble Mrs. (not Lady)—the younger children of all peers using, of course, the family name, with or without their forenames, according to their rank. {66}
e. If the lady to whom the title Hon. belongs in virtue of her father’s rank marries a commoner, she retains her title, becoming Hon. Lady, if she marries a knight or baronet; and Hon. Mrs., if her husband has no title.
None of these courtesy titles are inherited by the children of those who bear them, the third generation of even the highest peer being simply commoners unless raised in rank by marriage or merit.
Titles of unmarried women.