Otherwise known as Monty Python and the Quest for the Holy Grail, this was the first feature-length film done by the Monty Python troupe following the conclusion of Monty Python’s Flying Circus (not counting And Now for Something Completely Different, which is more a collection of sketches). Made on a shoestring budget, directed by two men who’d never helmed a film before, and rife with issues during production, it nonetheless became a cult classic and favourite film for British comedy fans. 2015 is the 40th Anniversary of the film’s release and in honour of that mark; here are ten interesting facts about this hilarious trip the Middle Ages.

Rock n’ Roll Funding

Done on an incredibly small budget, the Pythons found funding from an unlikely sources—rock bands. Groups like Led Zeppelin, Jethro Tull, and Pink Floyd helped get the money up for the production, with a portion of the funds coming from the Floyd’s album “The Dark Side of the Moon.” This is a trend that would continue later with The Life of Brian, when a large portion of the funding came from former Beatle George Harrison. When Harrison was asked why he funded the film, he responded “Because I wanted to see it.”

“It’s Only a Model”

While the exteriors of several castles (and a couple of models) are shown in the film, the Pythons only got permission to use one for filming interior scenes. The original plan was to use several castles owned by the National Trust of Scotland, but after the authorities read the script, they denied the group the right to film in any of the Trust’s castles, which left the Pythons with only privately owned castles as an option. Fortunately, the Earl of Moray, the owner of Doune Castle, had also given his permission. As a result, all interior castle scenes are filmed at Doune and redecorated to look like different sets. Today, the castle is open to the public and the audio tour is done by Terry Jones.

First Attempt

The film also represents the directorial debuts of both Terry Jones and Terry Gilliam, who decided that anyone named Terry got to direct the Pythons’ first film. Attempting to co-direct at the same time led to conflicts, so the Terrys split up the responsibilities with Jones handling the actors while Gilliam worked on the cinematography. They’d go on to direct the remaining Python films together and Jones would additionally direct Mr. Toad’s Wild Ride, while Gilliam’s lengthy directorial career would include such artistic classics as The Fisher King, Brazil, Time Bandits, Twelve Monkeys, Fear and Loathing in Las Vegas, The Imaginarium of Dr. Parnassus, and more.

Casting Gags

There are several great moments of casting in the film. Beyond the Pythons doing their usual bit of playing multiple roles, several other notable individuals appear in the film. John Cleese’s then-wife, Connie Booth, appears as the witch for Sir Bedevere’s scene. Michael Palin’s own son William appears in the film (as a photograph) for “Sir Not Appearing in this Picture”. Python songwriter Neil Innes appears three separate times as one of the self-flagellating monks, a squire who gets the Trojan Rabbit dropped on him, and Sir Robin’s lead minstrel. Lastly, though Cleese plays most of the Black Knight’s part, a local blacksmith named Richard Burton (really) plays the role after the Black Knight gets his leg chopped off, as Burton was missing a leg.

Talking to Himself

In addition to playing Arthur, Graham Chapman also provided the voice of the Gilliam-animated God. God’s appearance was based upon famous cricketer W.G. Grace. Chapman was also in the midst of alcohol withdrawal while filming. As such, no alcohol was kept on set and the Bridge of Death scene had to be completed with a body double because Chapman’s delirium tremens caused him to freeze up during the filming of it.

No Animals Were Harmed (Per Se)

The vicious Killer Rabbit of Caerbannog had parts of its fur dyed red to represent the blood of the knights that it spilt with its large, pointy teeth. Unfortunately, the dye used wouldn’t wash out afterwards and the rabbit’s owner was furious.

Hated It

Despite being very successful and one of the most-remembered films for all the Pythons, it isn’t a favourite for the Pythons, who prefer Life of Brian. Part of the reason for this was the miserable conditions on set. In addition to Chapman’s withdrawal, the Pythons were all wearing wool and it was quite cold and wet. Beyond that, the water heater at their hotel couldn’t provide enough hot water for everyone to get take a hot shower, so it was often a race to be the first one back to the hotel. Jones said filming the “Bring Out Your Dead” scene was one of the only times he’s seen Michael Palin upset, as the latter had to crawl around in mud and excrement, unsure of which mud was actually chocolate he had to eat for the film. When asked to do a seventh take, Palin threw such a fit it actually got a round of applause from Cleese and Chapman.

Creative Credits

By the time the Pythons actually got around to doing the credits, they’d run out of money. As a result, the credits were very simple and Palin decided to spice them up a bit by adding the Swedish subtitles and llama references. When the film was shown for the first time at Cannes, firemen rushed in at the end of the credits to evacuate the audience due to a bomb scare. The crowd didn’t leave at first because they thought it was part of the show.

Everybody was Medieval Fighting

In part due to the low budget, Chapman and Cleese did all their own stunts for the Black Knight scene. The two used heavy swords and some acrobatics for added realism. Connie Booth had brought her and Cleese’s young daughter to the filming, who during the fight turned to her mum and said “Daddy doesn’t like that man, does he?”

You’re Using Cocoanuts!

Another product of the film’s low budget, the Pythons’ couldn’t afford to ride actual horses during filming. The use of cocoanuts was thought up as a substitute and is one of the most well-known gags in Monty Python and the Holy Grail.