 Ben Barnes as Prince Caspian . Adamson said " Caspian is a coming of age and , to some degree , a loss of innocence story , with Caspian starting out quite naïve , then craving revenge and finally letting go of the vengeance . " While many readers interpret Caspian as a child , a passage in the novel mentions his age to be near that of Peter 's , so an older actor was sought to match Moseley . Barnes had read the novel as a child , and was cast in two @-@ and @-@ a @-@ half weeks after meeting with the filmmakers . He spent two months in New Zealand horse riding and stunt training to prepare for shooting . Barnes modelled his Spanish accent on Mandy Patinkin 's performance as Inigo Montoya in The Princess Bride , though he also had a dialect coach aiding him . Adamson did not expect to cast a British actor as Caspian , and said Barnes fitted well into the surrogate family of Adamson and the four actors playing the Pevensies . When cast , Barnes was set to tour with the Royal National Theatre 's production of The History Boys : producer Mark Johnson joked Barnes " probably isn 't the Nation 's favourite actor right now " . Barnes left England without telling the Theatre . They were furious when they found out that he had left them without permission , so they considered suing him for breach of contract , but decided against it . 
