The Crusade marked David Whitaker's first script for Doctor Who following his departure as the show's story editor.
Originally titled The Saracen Hordes, the four-part story takes the TARDIS to 12th Century Palestine, where Barbara gets kidnapped, Ian gets smothered in honey and eaten by ants, and the Doctor and Vicki attempt to settle a Royal Family feud.
The Crusade arguably boasts Doctor Who's first true guest star, acclaimed actor Julian Glover, who played Richard the Lionhart. Glover later went on to wear a big green rubber head and collect dodgy copies of the Mona Lisa in the fabulous City of Death. Before Glover was cast, Nicholas (The Brigadier) Courtney had been considered for the role of Richard.
The story also marks the first appearance in Doctor Who of actress Jean Marsh, who would subsequently join the TARDIS team as Sara Kingdom in The Daleks' Master Plan. She later married Jon Pertwee and almost made Battlefield watchable.
William Russell sneaked off for a well-earned holiday during episode three, having pre-filmed his encounter with those deadly ants. He had an arm double for the ant scene too. And who could blame him?
Due to the potentially sensitive content of the story, The Crusade was not offered for sale to several Middle Eastern countries, such as Iran.
For many years only episodes three - The Wheel of Fortune - remained unwiped in the BBC's archives. Perhaps, somebody thought it was that quiz show hosted by Nicky Campbell and Carol Smillie?
Luckily, in 1999, collector Bruce Grenville stumbled across a film print of episode one - The Lion - in Auckland, New Zealand. It was whisked back to the UK, spruced up by the Restoration Team and rush-released on video. The set also featured a CD of the missing episodes' soundtracks, specially-filmed linking scenes performed in character by William Russell as Ian. Oh, and The Space Museum, but nobody bothered to watch that.
By a stroke of good luck, John Cura's telesnaps for episodes two and four were also discovered in 1999, allowing the Cult team to combine images and clips from both sources to produce this Photonovel.
Whitaker's novelisation of the story was one of the very first Doctor Who books to be published. The hardback edition was published by Frederick Muller in 1966, years before Target Books began their Doctor Who range.