Batman prequel series Pennyworth is based on the surprisingly action-packed early life of Bruce Wayne's butler, Alfred Pennyworth, from DC Comics. Interestingly, the premise behind the show's story didn't originate from the comic books (though Alfred has an awesome origin story in the comics as well). Instead, it was a product of Christopher Nolan's Dark Knight trilogy and Michael Caine's celebrated take on Batman's butler.
Executive produced by Bruno Heller and Danny Cannon, Pennyworth airs on the premium cable network Epix. Set in 1960s London, the series follows a young Alfred Pennyworth, decades before becoming the butler and trusted ally of the Caped Crusader. Played by Jack Bannon, Alfred is a former soldier in Britain's SAS (Special Air Service) who forms a security firm. While in London, he crosses paths with the future father of Batman, Thomas Wayne (Ben Aldridge), and gets caught up in a conflict between two revolutionary groups.
Alfred's experience in the SAS is an important part of the character's comic book origin that actually came about as a suggestion from Michael Caine himself. Caine famously portrayed Alfred in Batman Begins, The Dark Knight, and The Dark Knight Rises. When Batman Begins was in production, Caine made up a backstory that involved Alfred being in the SAS when he meets Thomas Wayne for the first time. Batman Begins director Christopher Nolan ended up making Caine's idea canon in the movie.
Alfred's backstory has seen a number of retcons in the comics. Alfred's military affiliation hasn't necessarily been consistent. In the past, he's been associated with the Royal Marines, and in other continuities he has had no military experience at all. A 2014 Batman comic officially tied the character to the SAS.
Pennyworth leans heavily on Alfred's military background. In the series premiere, his two closest friends are Dave Boy (Ryan Fletcher) and Bazza (Hainsley Lloyd Bennett), who are both soldiers that Alfred served with in the SAS.
This aspect of Alfred's life in Pennyworth is owed solely to Michael Caine's contribution to the iconic character's backstory. Caine's impact on Batman lore is strongly felt in Pennyworth, where actor Jack Bannon portrays Alfred with a Cockney accent, which is something else that originated from Caine. For many fans, Michael Caine is the definitive Alfred, and due in part to the popularity of the Nolan trilogy, Despite the fact that Caine is just one out of a long list of actors who have played Alfred, Caine's Alfred is considered to be one of the most memorable iterations of Batman's butler.