Helen of Troy — the face that launched a thousand ships — is one of the most famously beautiful women in history. Wife and Queen of King Menelaus of Sparta, her alleged abduction by Paris of Troy led to the ten-year Trojan War. But did she really exist and where is she documented?

Laurie Maguire is a Professor of English at Oxford University and an expert on the Renaissance, particularly Shakespeare. Intrigued by Helen’s story, she has written a literary biography. Helen of Troy: From Homer to Hollywood takes us from Homer’s The Iliad to the 2004 Brad Pitt film Troy, yet by the end we are no nearer to understanding who Helen was.

The book took 13 years of Laurie’s life, three of them full-time. So what made her want to write it?

“I first came across references to her continuously, accidentally,” she explained, when we met in her room at Magdalen College. “Whatever century I was teaching, there was something that someone had to say about Helen of Troy, usually something that was full of hatred. And I was fascinated by the notion of a figure who in every century had attracted attention, and usually very violently negative attention.”

Soon documenting Helen became an obsession. After reading the book, it is not hard to see why as this paragon of beauty is impossible to pin down. No-one knows whether she really existed as a Bronze Age princess or was just a mythological Goddess figure. “The one fact about her is that she has a literary existence,” Laurie explained. “And so it was a biography of the literary character that I wanted to write. I wanted to document her story as told by storytellers and look at continuities, discrepancies, difficulties and changes in attitude as historical periods changed.”

Recognising that a chronological history would be hard to read, Laurie wrote the book thematically under chapters headed Narrative Myth, Beauty, Abducting Helen, Blame, Helen and the Faust Tradition and Parodying Helen. She mixes explanations with quotes from ancient and modern texts, films and plays. It is a neat conceit that shows just how widely Helen has entered our consciousness.

The chapter on beauty is by far the longest, which is unsurprising given that Helen is perhaps best known for being the most beautiful woman in the world. Yet there is little description of that beauty. Laurie said: “If she is indisputably the most beautiful woman in the world, as soon as you give details, you render that beauty disputable.”

She thinks that this is in part why the 2004 film Troy was such a disappointment. In a later chapter that looks at Marlowe’s famous quote about the face that launched a thousand ships, Laurie describes how Diane Kruger, who played Helen, was described as “a Helen who couldn’t launch a dinghy”. It is cruel, but illustrates the point perfectly.

What did Laurie find out that surprised her? “The focus of the book for a start,” she replies. “I was going to be using Helen as a touchstone to write a cultural history of misogyny.” However, she quickly found out that she was trying to tell a story of someone who wasn’t in their own story. “You know that lovely little poem? ‘Last night as I went up the stair, I met a man who wasn’t there. He wasn’t there again today, I wish, I wish he’d go away.’ There was that kind of liminality about the whole project; that she’s totally haunting every narrative and you as a writer, but the concrete material reality in the middle is shifting and elusive.”

This vacuum is at the heart of the book. As Laurie writes: “We cannot know Helen because we experience her in the already-mediated form of story; we further lack knowledge of her because she is absent.

"Helen is remote, self-contained, sealed in her beauty, the narrative equivalent of the Mona Lisa smile.”

It is what also makes the book maddeningly compelling. There is a tapestry of literary allusion where you may learn about the writers and the times in which they lived, but never about the subject. One can quite see why it became an obsession.

“It was a very hard book to let go,” she admitted. “I did not want to stop thinking about her and I’m still coming across references to her in things.”

However, Laurie is also pleased to be moving on. “I have enjoyed teaching enormously this year,” she said. “This cloud that’s been hanging over me has gone, in terms of always trying to find another hour in the week to read another Helen thing.” She can also enjoy her life in Oxford, whose beauty she greatly appreciates. She said: “It massages your soul on a daily basis.”

Helen of Troy is published by WileyBlackwell at £17.99