Hans Zimmer was originally attached as the film's composer but was replaced by Harry Gregson-Williams. A few weeks after this, the opposite occurred for another film: Zimmer replaced Gregson-Williams for the scoring duties of Madagascar.
King Mohamed VI of Morocco, is a friend of director Ridley Scott and he personally provided the production with a detachment of 1500 military personnel and equipment; oftentimes these personnel depicted both Christian and Muslim armies in the film, with simply a change of costume and a shift in location between scenes.
William Monahan's first draft of the script was 186 pages. Executive producer Lisa Ellzey was worried that when such a large script was submitted to Fox for budget approval, they would balk at the length, so she called what she refers to as a 'parenthetical meeting'. According to Ellzey, almost every piece of dialogue in Monahan's script was preceded by a parenthetical description of how the lines should be spoken. Ellzey removed every single parenthetical (much to Monahan's chagrin), and thus managed to get the page count down by 20 pages before sending it to Fox.
There were roughly 12,000-15,000 costumes made for the film, and each one had 13-15 separate components (helmets, boots, gloves, several pieces of chainmail, belts, scabbards etc).
Three 60-foot siege towers were built for the film, using the technology of the period. Each one weighed 25 tons. To accomplish the scene where a number of siege towers collapse, one of the real towers was knocked over on set and filmed from 11 different positions and locations. Various shots of the single tower falling were then composited together to give the impression that several towers have collapsed in different ways and in different directions.
During the last day of the siege if you look closely you can see a burning siege tower, during production one of the siege towers caught fire and was subsequently burned down. One of the charges for the firebombs hadn't been put out properly and was left smoldering over night, until it eventually caught the tower and lit up. Both director/producer Ridley Scott and production designer Arthur Max liked the aesthetic of the burnt tower, and decided to use it in the film.
William Monahan was brought to the attention of Ridley Scott by Scott's associate, Lisa Ellzey during filming of Scott's previous film Matchstick Men with a script titled Tripoli, intended to be a Russell Crowe vehicle. Ridley Scott would work on Tripoli in the evening after shooting Matchstick Men during the day. He and his team would then have story meetings all weekend. Indeed, Tripoli had effectively gone into preproduction. All the department heads had been appointed, Branko Lustig was working on a production schedule and budget, the major roles were being cast, design and artwork was bring done, models were being built, locations had been chosen. Indeed, some of the set was actually being built. The film was even greenlit twice, but on both occasions, things fell apart. It was around the time of the second collapse that William Monahan delivered his Kingdom of Heaven script. Scott had always wanted to make a Crusades movie, and much of the ideas and metaphors from Tripoli were incorporated into Kingdom.
Officially, the opening scene, The Crossroads was the first scene shot in the movie, on 12 January 2004. The little short of Godfrey's flashback was shot unofficially two days earlier. Balian's fight with the cavalier over the horse was the very last scene to be shot.
The shipwreck sequence was the last scene to be added before the film's release. Since it is too expensive to build one ship from scratch only to destroy it, Ridley Scott opted to use a combination of outtakes of the siege of Jerusalem, shots of Balian with his attire digitally altered, a CG model of a ship, and finally archive footage of a heavy sea storm and outtakes from his own earlier film White Squall. The creation of this 'non-existent scene' is explained in detail on the 4-Disc Director's Cut DVD.
The set used for the Kerak courtyard was actually shot on the northern wing of the Jerusalem set. By shooting at the opposite side, the production managed to save about $5 million.
Edward Norton was briefly considered for the role of Guy, but upon reading the script, he lobbied for the role of King Baldwin. Because the king appears behind a mask, he requested not to be credited. However, his name was put back in the video releases of the film.
After the pitching of this film, studio marketing executives took it to be an action-adventure hybrid rather than what Ridley Scott and William Monahan intended it to be: an historical epic examining religious conflict. 20th Century Fox promoted the film as an action movie with heavy elements of romance, and in the advertising campaign, they made much of the 'From the Director of Gladiator' slogan. When Scott presented the 194 minute version of the film to the studio, they balked at the length and studio head Tom Rothman ordered the film to be trimmed down to two hours, feeling people wouldn't go to see a three hour movie. Ultimately, Rothman's decision backfired as the film gained mixed reviews (with many commenting that the film seemed 'incomplete') and under-performed at the US box office.
After the team arrived in Morocco, an article appeared in the Daily Telegraph on January 20th, 2004 claiming that the film "panders to Osama bin Laden". However, the writer of the article was quickly exposed as not having seen the screenplay. Subsequently however, a copy of the screenplay was leaked to the world's press, and provoked a strong reaction in terms of its depiction of Muslims. In an article on August 12, 2004 Professor Khaled Abu el-Fadl wrote, "I believe this movie teaches people to hate Muslims. There is a stereotype of the Muslim as constantly stupid, retarded, backward, unable to think in complex forms". This new sway in criticism greatly concerned King Mohamed VI, who came to fear for director Ridley Scott's safety, and as such, Mohammad provided Scott with four bodyguards.
To create both the theatrical cut and the Director's Cut, editor Dody Dorn worked for 15 months straight - the average film takes at most, 4 or 5 months to edit.
The movie was not cut on film but was instead cut using a Digital Intermediate (the first time either Ridley Scott or editor Dody Dorn had ever used a DI). Originally, the plan was for only the siege to be cut via DI, but due to the level of complexity in the editing and due to the fact that so many things were changing so often, it was felt prudent to cut the film using a DI rather than the original negative.
The first cut of the film presented to the Fox executives was 186 minutes long. This had been taken from a 280 minute assembly edit (in the assembly, the actual siege itself was 45 minutes long). The main thing the executives questioned was the subplot involving Sibylla's son, as they felt this was Balian's story, and his story didn't need that particular plot line. Indeed, even during pre-production itself, executives had ordered writer William Monahan to write a version of the script without the Baldwin V plot, and Ridley Scott shot the film in such a way that the plot could be easily cut.
For the scene where the Templars attack the caravan in the desert, 143 extras, 60 military personnel, 125 horses and 60 camels were used, with the same stunt riders portraying both the Templar attackers and the Saracen victims. For the Battle of Kerak, 400 extras and 200 horses were used.
At any given time during production there were seven different departments working separately as offshoots of the props department: the smalls department (kept all the small props together), the drapes department (made anything involving fabrics), the dying department (aged props as needed), the paint department (painted the props), the model-making department (made anything that could not be built to scale), the leather department (made anything of leather), the woodwork department (made all the furniture and wooden props), and the metal work department (made all metal props).
In the 'burning bush scene' in the Director's Cut of the film, Balian's horse jumps as the camera pans across the desert, just after the character of the Hospitaler (David Thewlis) has 'disappeared', thus enhancing the sense that the character is a spirit of sorts. According to director Ridley Scott, the horse did this completely spontaneously as the scene was being shot.
Both director Ridley Scott and writer William Monahan felt that the unnamed character played by David Thewlis was an embodiment of God, or at the very least, an angel on a mission from God. This is not at all apparent in the theatrical cut, but in the Director's Cut, there are two scenes which strongly hint at it - one where the character seemingly disappears after a conversation with Balian (Orlando Bloom); the other where he seems to 'resurrect' Balian after being attacked by three assassins.
The screenplay originally began with Balian (Orlando Bloom) awakening after the shipwreck. Writer William Monahan had wanted to begin the story with the death of Balian's wife in France, but had feared that that would make the screenplay too long. When Ridley Scott became interested in the project, he told Monahan not to worry about length and to begin the screenplay where he wanted to begin it.
The reason Jeremy Irons' character was renamed Tiberias (as opposed to his 'real' name, Raymond III of Tripoli) was because the studio felt audiences would get confused with two major characters both having names beginning with R (the other being Raynald de Chatillon (Brendan Gleeson), and so they ordered writer William Monahan to change the name of one of them.
After being cast as the Hospitaler in the film, David Thewlis visited the Hospitalers' Museum at St. John's Gate in London, near where he lives. Whilst there, he discovered that his flat was actually built on the remains of the old priory of the Hospitalers' headquarters.
After being cast in the role of Godfrey, actor Liam Neeson realized he knew nothing about the Crusades and began his research with The Complete Idiots Guide to the Crusades by Paul L. Williams, a book Neeson calls "extremely informative".
Two practical trebuchets were built for the film. The arms could pivot 56 feet and fire loads of 100 pounds some 400 meters. During filming, the arms of one of the trebuchet towers snapped due to the extreme temperature changes which dried the wood in the arm. The snapping of the arm can be seen in the behind the scenes footage on the 4-Disc Director's Cut DVD.
As he had done in Huesca, production designer Arthur Max used a real kasbah when constructing Ibelin, and simply built an 'extension' onto the existing structure. The set was built primarily by local craftsmen using traditional building techniques (eg mud bricks were made on-site from local earth and straw, doors and window frames were hand-carved from local palm trees, roofing tiles were hand-thrown and hand-fired).
Most exterior filming took place in Ouarzazate, Morocco, where Ridley Scott had also filmed Gladiator and Black Hawk Down. A massive replica of Jerusalem was constructed in the desert; the set contained 28,000 square meters of wall and used 6000 tons of plaster. The front of the set was 1,200 feet long, and the walls were 56 feet tall.
The French village at the start and end of the film was built near Huesca, a small city in northern Spain. The castle seen in these scenes is a real crusader castle built in 1076, Castillo de Loarre. As he would do in Morocco when building Ibelin, production designer Arthur Max decided to use traditional building techniques and local craftsmen. In Galicia, he found craftsmen who still did slate roofs, thatching and stone dry-walling, and these men were employed to build the village set.
Ridley Scott offered the small role of English King Richard I to Russell Crowe, but due to scheduling conflicts, Crowe was unable to do it. The part eventually went to Iain Glen.
When Sibylla shows Balian the rings she wears and explains where she got each of them, she points to one particular ring and says that this one came from France and that she's never been there. In reality, Eva Green was born and raised in Paris.
Orlando Bloom had just completed filming Troy when he received the screenplay for Kingdom of Heaven and was initially reluctant to even read the script for another historical epic. Knowing it was being put together by Ridley Scott convinced him to give it a chance.
The pomegranate that Sibylla feeds Balian after their first bout of lovemaking in a darkened room had to be digitally enhanced to be clearly seen among the muted colors.
The trivia items below may give away important plot points.
According to journalist Robert Fisk, at several screenings in Beirut, Muslim audiences rose to their feet and applauded during the scene where Saladin (Ghassan Massoud) picks up a fallen crucifix and places it back on top of a table after the siege of Jerusalem has ended.
Several alternative endings were shot for the film. Orlando Bloom's preferred ending was as Balian rides past the pilgrims as they leave Jerusalem, he doesn't see Sibylla (Eva Green), but returns to France alone and resumes his life as a blacksmith. In another, version, he does see her, and they speak and ultimately take one another hand's, and the film ends with them walking away into the desert with the other pilgrims. In another version, he sees her, they talk, and then we cut to him arriving in France alone.
For the final scene, when Balian runs his hand along the sapling planted by his wife, and sees that it is starting to bud, a subtle digital effect plays a pivotal role in the shot - the plant used in the scene had no buds, so all the buds seen in the shot are 100% CG.