The never-before-seen script will be partially published for the first time in a book about the television show, "The History of the Black Adder," which will be released later this week, the BBC reported Saturday.
Curtis gave the book's writer, Jem Roberts, a copy of the script during research for the book.
"[Curtis] wrote on the script that one of the reasons it didn't get used was because it was a strange cross between 'Fawlty Towers' and 'Life of Brian,' " Roberts said. "He didn't think he was going to make it compare to either of them. That's his reason for it never getting any further than it did."
The episode would have featured Blackadder, played by Rowan Atkinson, as the owner of the inn where Joseph and Mary seek a bed on the night of Jesus' birth.
Curtis said he didn't go through with the episode "for fear it would cause too much offense."