BBC Diplomatic Correspondent
Who has greater claim to Jerusalem and its holy places, asks Orlando Bloom as he exhorts his Crusader followers to defend the walls of the city against the advancing Muslim army of Saladin.
The Kingdom of Heaven has faced accusations of political correctness
It is a question that still resonates today and it is one of the reasons why Ridley Scott's new film, Kingdom of Heaven, is attracting such interest.
In a post-9/11 world where some academics and commentators are talking about a new clash of civilisations between Islam and the West, it is bound to be controversial to revisit that great earlier clash that saw western Christendom's repeated efforts to seize and hold Jerusalem.
History matters. And cinema's portrayal of history matters too. Kingdom of Heaven may be a medieval epic set in 1187, just before a Crusader army was wiped out at the battle of Hattin. But it has already been criticised for being a very 21st century, politically correct, view of the Crusaders' world.
Professor Jonathan Riley Smith of Cambridge University is probably Britain's leading historian of the Crusades. This film has made him angry, for the Crusades are, at the moment, a rather hot subject.
"In the Islamic world," he told me, "crusading is believed by many Muslims to be still in train.
"What has been believed now for a century in the Middle East is that the West, having lost the first round of the crusades in the Middle Ages, re-embarked on crusading in the late 19th century, using the techniques of commerce, banking, politics, diplomacy, backed of course by power.
"In those circumstances," he said, "the Crusades have to be treated very, very carefully."
So what is wrong with the history as portrayed in the film?
Balian probably wasn't the nice man played by Orlando Bloom in the film
The story opens during a period of apparent truce between the Christian ruler of the Kingdom of Jerusalem, King Baldwin - a man hidden behind a silver mask - and the great Muslim commander, Saladin. Balian, played by Orlando Bloom, is the film's hero; the knight who takes command of Jerusalem's defences.
But Professor Riley-Smith says that the film has taken real people and simply re-manufactured them. There was no silver mask and the real Balian was known to be harsh to his Muslim tenants.
The Crusading Order of the Knights Templar - who are the film's villains - were no better or worse than any other Crusaders, he believes.
Not all historians have been quite so dismissive. Carol Hilenbrand, professor of Islamic history at the University of Edinburgh, said she believed the film did represent an attempt to grapple with serious issues.
She didn't think that the sort of contacts and mutual respect portrayed in the film between Baldwin and Saladin were out of keeping.
Kingdom of Heaven treads a road paved with good intentions. Its Muslim characters are real people. And there is good and bad on both sides.
The battle scenes are orchestrated in a way that only Ridley Scott can. As a film, I enjoyed it. But some historians remain fearful that epic cinema risks creating epic misunderstandings about the past.
If you really want to know about the Crusades, the historians say, by all means go and see the film, but then go out and buy a good book.