I believe you've arleady seen it.
So, the story in short and without the interesting things : Orlando Bloom is Baliant, a french blacksmith, son of a french knight, Godefroy d'Ibelin (Liam Neeson(but Baliant doesn't know it). Godefroy came back from the Crusades, go to see Baliant, and convince him to go to Jerusalem (baliant has his own reasons, you'll see them if you go see the movie

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And then, when they're in Jerusalem, there is the relationship problems : between the french knights and the muslims, between the french knights and other french kinghts, between the king of Jerusalem, Baudoin the IVth, and the Prince of Antioche, Renaud de Châtillon, etc.......Some want war (the templars, Guy de Lusignan, Rendaud de Châtillon), some want peace (Baudoin, Tiberias, the governor of Jerusalem)...
There is no manicheism muslim/christians : in the both camps, there is some ugly men, and very honorable men.
If there is a message, it would be : don't make war for religion, love the other men.
And : the religion is not in the cathedrales, in temples, it's in heart, religion makes that people become more fair.
It's not at all anti christian or anti muslim. (one of the last pan of the ovie is Saladin taking a cross, which is on the ground, and he puts it on a table...kinf of restauration

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So, it's not an action/history movie without some philosophy, it's quite well n this point, on the historical point of view it's good too, and the battle secènes are really nice...the siege of Jerusalem by Saladin.....wow !