Henry Fitzwilliam, the Earl of Matlock married to Alice, Countess of Matlock
Their eldest son, David Fitzwilliam, Viscount Renham married to Susannah, Viscountess Renham
Their younger son, Colonel Richard Fitzwilliam (from Pride and Prejudice)
A grown daughter Lady Mary in one of my books
A very late, adored daughter of four years old Lady Rachel in Imagining Mr. Darcy
The Earl of Matlock had two sisters the elder is Lady Catherine de Bourgh (from Pride and Prejudice) The younger was Lady Anne Darcy (from Pride and Prejudice)
The earl’s family home in London is Matlock House and their country estate is Hayden Hall, in the hamlet of Matlock, about ten miles from Darcy’s estate of Pemberley, near Bakewell.