Too Dangerous for a Lady tells the story of Hermione Merryhew and Mark Thayne.
It opens in Sep 1817 at Ardwick, Lancs.

Mark Louis Thayne, Viscount Faringay aka Ned Granger.

Lady Hermione Merryhew, sister of Roger Merryhew.

They met at ball in May 1811.

More info on the book is available here: Too Dangerous for a Lady