In 1684, the first novel in this genre was published. It remained very popular throughout the 18th and 19th centuries. This epistolary novel (based on a series of letters) was written in 1871 and was the bases for Jane Austen's novel 'Lady Susan'. She shelved it and it wasn't published until 1871 after her death. Many agree that shelved material should lie where it is left.

Dendy site
Lady Susan finds herself in an improvised position. Her husband is dead. In a time when women needed a husband to provide a position in society is the basis for this movie. She [Kate Beckinsale] is beautiful, totally unscrupulous and wants it all. She wants to keep her lover (what's new?) while finding a man who is 'vastly rich, rather simple'.

official trailer
She is also 'the most accomplished flirt in England'. At the same time she needs to find a husband for her daughter, who has been refused re-entry to her school because 'the fees are far too high to contemplate paying'.
So why go to this film? The repartee is excellent, the costumes are breathtaking, as are the scenery and settings for this film. It is set in Northern Ireland where there are 56 castles to choose from and the 3 featured are majestic. Well-known actors are featured in the vast cast of characters.

courtsy of New York times
Whit Stillman, the writer and director of 'Love and Friendship', described himself as a' Jane Austen nut'. Perhaps this film is aimed at the 'nuts'. He rewrote Austen's 'flawed', shelved novel for this film. He didn't want an ersatz (inferior imitation of the original), maybe that is what he has achieved.
The music chosen by Mark Suozzo is of the period. In particular, the inclusion of music from Mozart's opera buffa 'Cosi Fan Tutte' (women are all like this) is saying it all. The times change, but does the scheming? Beautiful people doing what they had to do to survive in the 18th century. This can translate to marriage games in any period.
This is an elegant, witty tale that Austen didn't want published. At 20 this was her first novel. Dear reader, you can judge if Stillman hasn't produced a classic or an ersatz and should have left things alone.