A Google user
This funny and touching book, half Gothic romance and half comedy of manners, was one of the bestsellers of its day. Its author has never been positively identified, but she or he was a great influence on many later authors. Fatherless Fanny, the mysterious but charismatic orphan left on the doorstep of a select boarding school, her amusing friends, and her strange destiny were the delight of generations. If you like Georgette Heyer or Frances Hodgson Burnett, you owe a debt to Fatherless Fanny.
And no, I don't why Google has this classified as erotica.