Entertainment reporter, BBC News
300 faces charges that it insults Persians
As the blood sprays and body parts are scattered in the sword and sandal blockbuster 300, the first thought on your mind may not be "have they got the armour right?".
But crying foul when Hollywood plays fast and loose with facts is not just for history nerds.
The heroic westerner vs tyrannical Persian theme of 300 - based on Frank Miller's graphic novel about the Battle of Thermopylae in 480 BC - has sparked indignation from some commentators in the US, and brought protests from the Iranian authorities.
And while not every movie provokes an international incident, bending the facts to fit the film is nothing new - as film historian Kevin Brownlow reveals.
"In his 1927 epic Napoleon, director Abel Gance showed his hero at the Club des Cordeliers when the Marseillaise was first sung. He was informed that Napoleon had not been present. 'He is now,' he said."
A particular low point in the relationship between film and fact was 1936's The Charge of the Light Brigade.
"Instead of being the result of a military blunder during a war in Southern Russia," said Mr Brownlow. "The doomed attack became an act of personal revenge in India.
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"They got so many things wrong you wonder why they bothered to pretend it was history at all."
Star of The Charge, Errol Flynn, also took the role of General Custer in They Died With Their Boots On, where he died a hero's death with his men.
"Some evidence suggests many of the US soldiers were shot in the back and were therefore running away - but who would want to see that?," says Mr Brownlow.
The political power of films was understood by Stalin who, eyeing the growing belligerence of the Nazis ordered a rousing account of 13th century warlord Alexander Nevsky who had defeated invading German knights.
Mr Brownlow said: "Such was the rush it was shot in July heat on artificial snow. But no sooner had it been finished than the 1938 Hitler-Stalin Pact had been signed and the picture had to be put on the shelf.
"It came off the shelf just as quickly when Hitler invaded in 1941."
Things got little better in the post-war era.
US journalist Lowell Thomas helped create the legend of Lawrence of Arabia with his filmed reports and was even included in David Lean's 1962 epic.
"Despite being confronted with perhaps the most brilliant spectacle in talking picture history," recalls Mr Brownlow, "He said 'The only accurate things in Lawrence were the camels and the sand'."
While it would be hard to make a film about as volatile region as the Middle East without drawing protests from somewhere, British audiences can be almost as prickly.
American War of Independence epic The Patriot, starring Mel Gibson, was condemned for portraying the British soldiers, or Redcoats, as child-murdering criminals.
So vocal were the objections that the then Culture Secretary warned there was a difference between "putting a gloss on something and distorting things beyond all recognition".
By then, Gibson had developed a reputation for sticking it to the British.
A planned film about Thatcher is likely to spark controversy
Dr Martin Farr, a lecturer in Politics at the University of Newcastle, said: "Braveheart is one of the most striking examples of a film influencing the real world.
"I went to a screening in Glasgow and the SNP were handing out leaflets. During the film, every English death was greeted with a huge cheer."
Just to show it was not a fluke, Gibson has gone on to upset both Jews, with The Passion of the Christ, and Mayan central Americans, with Apocalypto.
Dr Farr emphasised popular films and academic history are different creatures: "The demands of camera is such that you can't be as fair in 90 minutes as you can in 100,000 words.
"But there is a line that moviemakers should not cross. In U571 the audience was told that the US, rather than the British, navy seized Germany's Enigma code machine.
"It was one of the most significant moments of the Second World War and to alter it so fundamentally is unfair."
Such controversy shows, believes Dr Farr, a basic fact about history.
"It's never settled. There is never one view of what happened and why. Just imagine the fuss that is going to be caused when they make a film about Margaret Thatcher."
300 opened in cinemas across the UK on 22 March