Brain Snacks: Tasty Tidbits of Knowledge
Harry Lloyd, whom you may know for playing Viserys Targaryen in Game of Thrones, performed the part of Ferdinand in a 2012 state production of The Duchess of Malfi. Apparently he's very good at playing psychotic brothers with dubious feelings toward their sisters. (Source.)
In the 1998 film Shakespeare in Love, you may have noticed that Shakespeare keeps running into this weird little boy dangling rats by their tails and talking about how much he likes the stabbing and poisoning parts of plays. That boy is… you guessed it… John Webster. (Source.)
Here's how it really went down: The Duchess and Antonio were real people, who were married in the early 1500s. The real historical Team Antonio and Duchess lived openly as a married couple, but they met roughly the same end as the fictional TAD. The Duchess, along with two of her kids and her maid were captured and taken to a castle, and were never seen again. Antonio himself was later stabbed to death in a street, and the Duchess's one surviving son, Alfonso (who, unlike in the play, was actually the son of old Duke of Malfi), went on to rule Malfi.
Bosola was based on a guy called Daniele da Bozolo, who was actually the second assassin hired by the Duchess's brothers—the first one they hired warned Antonio about their plan. This is super-neat, because it means that Bosola, a notoriously confusing character because of his shifts in attitude, is actually based on two totally separate people.
Anyway, while a lot of the plot is loosely based on what really happened, almost all of the really grisly, gut-wrenching bits are Webster's own invention: the Duchess's torture, complete with lunatics, severed hands and mannequins of her family members, along with Ferdinand's lycanthropia and the final three-way murder showdown, are all Webster. (Source (pg. xi-xiv).)