Dramaturgy

"This is the difficulty - this is where we sometimes have to compromise with historical reality," declares Lloyd Llewellyn-Jones. "This" is the uncovering of Angelina Jolie, normally a matter of routine in the actress' films, but not, according to Llewellyn-Jones, in Oliver Stone's forthcoming Alexander, a Hollywood life of the compulsive Macedonian conqueror.

For him, it is an academic-cum-professional issue if Jolie, who plays Olympia, Alexander's mother, reveals so much as her expensive face in this role. "An actress like Angelina Jolie cannot be expected to veil her face," Llewellyn-Jones concedes, but he adds: "The ladies of ancient Greece were as likely to cover up as those of Alexander the Great's Persian opponents."

Llewellyn-Jones is a lecturer in classics and ancient history at Exeter University and an expert on Greek and Persian dress. He is also one of the small band of historians enjoying a spell in the limelight as advisers on the current crop of "sword and sandal" films.

The house lights dim for Alexander on November 5, when Colin Farrell will sally forth to conquer much of the known world, including Rosario Dawson's Roxanne. Those pretend-Persian extras who escape Farrell's sword may soon be in for a drubbing from Leonardo DiCaprio. If, that is, Baz Luhrmann secures financing for his version of Alexander, which he promises will be "the world's biggest road movie". Then there is Wolfgang Petersen's Troy, on general release this week and starring Brad Pitt and Orlando Bloom. At least one Hannibal film, a Cleopatra and a brace of Boadiceas/Boudiccas is also in the pipeline.

Investors' and audiences' interest in sword and sandal films began to flicker after the Richard Burton and Elizabeth Taylor Cleopatra of 1963 - four hours long, way over budget and, according to one critic, "more block than buster". The genre, Llewellyn-Jones argues, is being reinvented because our world, like Alexander's, is "divided by East-West conflict".

The Athens Olympics may also be a factor this year.

Llewellyn-Jones credits Ridley Scott with reviving interest in the genre with the commercial success of his 2000 film Gladiator, which he hopes to reprise next year with Kingdom of Heaven, a film set during the Crusades.

Llewellyn-Jones dismisses Gladiator as "hokum, fantasy", adding that Stone may have unveiled Jolie, but at least there are no scantily clad slave girls in the Cecil B. DeMille tradition.

Still, film consultancy sounds nice work if you can get it, so how do you get it? In Llewellyn-Jones' case, he was "discovered" while lecturing at the British Museum with Robin Lane Fox, reader in ancient history at Oxford and author of the 1973 book Alexander the Great. He was working on Alexander and asked Llewellyn-Jones if he might be interested. Lane Fox made a BBC film about his experience advising Stone called Charging for Alexander. The title relates to Lane Fox's stipulation in his contract that he should be among the first 15 horsemen in any Macedonian cavalry charge.

Whether the footage survives editing remains to be seen. Stone credits Lane Fox's book with being his "main guide" on the historical aspects of his film. "He didn't say he would always take my advice," says Lane Fox. "I respect that - he's a film-maker." The consultancy quickly grew in scope, ranging from late-night calls on whether Ancient Greeks flossed, to weightier discussions on Alexander's battle plans. As to whose history triumphs, Lane Fox's or Stone's, the academic is diplomatic. Stone's interpretation is "very strong" but "not necessarily wrong".

Llewellyn-Jones says Stone has striven for a documentary-standard realism in matters of dress as far as he can, even where reference material is often non-existent, vague or contradictory. And he doesn't play fast and loose with known facts in the plot. But he adds: "Stone is interested in conspiracy theories, and some of the themes you find in his other historical films will no doubt rear their head again in Alexander." He will not be drawn on who kills Alexander in the film, but says: "Among academics, the jury is still out on how Alexander died. I think Alexander was probably poisoned. Macedonian generals could have done it, members of the clergy or Persian nobility - there are even bickering wives and lovers."

Lesley Fitton, curator of Greek Bronze Age antiquities at the British Museum and author of The Discovery of the Greek Bronze Age and Minoans, says film-makers want historical advisers to give them "confidence, a safety net - somebody there who will freak if they do something totally weird and anachronistic".

The museum has launched a "Greek Summer" exhibition to coincide with the release of Troy. This includes a display on the ancient Olympics and another, "Troy re-told", on how different interpretations of a story, which began as oral history retold by Homer 500 years after the event, sometimes come into conflict with archaeological evidence.

Fitton's consultancy on Troy began with a simple query about the type of script that should go on an ancient map, and then grew into wider questions to do with gods, gesture and ritual. It ended with Fitton flying out for a week's filming in Malta in return for a donation to the museum.

She admires Gladiator - and Troy - not as a historic reconstruction, but as "a good film which tells a good story, and might therefore interest people in the history of its period". For this reason, she is not among those purists who, she expects, "may have 10 million blue fits" when Troy ends on a distinctly unHomeric note. Helen isn't restored to husband Menelaus in Sparta, but walks off into the sunset with Paris, who somehow isn't killed at Troy after all.

"A lot of people have said to me, 'How can you even remotely be associated with a film that takes such dreadful liberties?' I just turn round, rather naughtily, and say, 'Well, if Shakespeare had asked me to be an adviser on Troilus and Cressida, I dare say I would have done, although that's an entirely invented medieval addition to the Troy myth, as is Chaucer's.'"