The dramatic scene performed on stage by Marguerite, and later by Louise, is from "Phaedra" by Jean Racine (1677).
Sir Ian McKellen and Timothy Carlton appear in this movie. Decades later, McKellen appeared in The Hobbit: An Unexpected Journey (2012), The Hobbit: The Desolation of Smaug (2013), and The Hobbit: The Battle of the Five Armies (2014), along with Carlton's son, Benedict Cumberbatch.
Julian Fellowes (Prince Regent) also played the Prince Regent (the future George IV) in Sharpe's Regiment (1996)
There is another Sharpe connection - Christopher Villiers (Lord Anthony Dewhurst) appeared as Colonel Bampfylde in Sharpe's Siege (1996)