Her fans called her La Divina, the divine, and Maria Callas seemed to think so, too. 

‘I have been touched by the hand of God’, said the singer hailed by her devotees as the greatest ever soprano.

A new biography, drawing on her previously unpublished letters, makes exactly the opposite claim, however: Callas might have been cursed for all the suffering and betrayal she endured in her glittering but turbulent life.

She was regularly drugged by her violent lover, Greek shipping tycoon Aristotle Onassis, so he could sexually abuse her; swindled by her husband and father, and blackmailed by a mother who tried to force her into prostitution.

‘Callas the singer may have had the upper hand in the music world but Maria the woman was a victim of circumstance,’ according to biographer Lyndsy Spence, author of Cast A Diva: The Hidden Life Of Maria Callas.

Callas has been the subject of almost 30 biographies, but Spence has been able to shed revealing new light on the operatic superstar after obtaining access to boxes of her letters that have been sitting unexamined in an archive at Stanford University, California.

The correspondence with her husband and agent, Giovanni Battista Meneghini, shows ‘she was really so subvervient and obedient to him, and I started to realise that is who she was as a woman’, Spence told the Daily Mail.

‘She was such a submissive person and that really contrasts with Callas the diva. And when you’re that way inclined, of course you attract abusers.’ And that includes Meneghini, Onassis and even her own parents, adds her biographer.

Nobody abused her quite like brutish Onassis, however. He ‘tortured’ her emotionally and physically during their relationship before cruelly and infamously dumping her for Jackie Kennedy whom he married in 1968.

From the diaries of a close friend of Callas, Spence has discovered that Onassis would ply the singer with the powerful hypnotic sedative methaqualone, also known as Mandrax, to which she became addicted along with Nembutal, a barbiturate used as a pre-anaesthetic.

She took it willingly, but with Callas effectively sedated, Onassis — whose ‘depraved’ sexual requests shocked even the notorious Paris brothel keeper Madame Claude — was able to sexually abuse the singer in demeaning ways, says her biographer, she wouldn’t have permitted if she had been fully conscious.

Spence also claims Callas was at the time already suffering from ‘mental health issues’ as she coped with the twin pressures of her career and ageing. The pressures were compounded by her discovery that Onassis was making heavy use of Madame Claude’s ‘girls’ and even had the bedroom at his Paris home decorated like a brothel.

Abusive Aristotle Onassis with Callas. She was regularly drugged by her violent lover, Greek shipping tycoon Aristotle Onassis, so he could sexually abuse her; swindled by her husband and father, and blackmailed by a mother who tried to force her into prostitution

It was to remind women, he said, of what they were. ‘The best girl is a girl you never see again,’ was a favourite Onassis maxim.

He was ugly and crude but Onassis exuded a powerful sexual magnetism and Callas was unable to resist. He had a preference for emaciated, androgynous-looking women and Callas — who was prone to weight gain and suffered from eating disorders throughout her life — responded by going on a dangerous crash diet, weighing every morsel of food and becoming emaciated herself so she could ‘fit his ideal’.

Spence says she can also definitively dismiss lingering claims that Onassis and Callas had a secret child together. The singer was indeed pregnant with his baby in early 1960, she says, but — citing Callas’s letters to her lawyers — she suffered a miscarriage.

She was still married to Meneghini at the time and he threatened to take her child off her, adds Spence. ‘But of course she had a miscarriage four months later and there was no child.’

While with Onassis, Callas also suffered another miscarriage and underwent an abortion.

Throughout her life, it was a similar story: a veneer of incredible professional success, acclaim, glamour and wealth concealing an undercurrent of misery and degradation.

Callas, who was born Sophie Cecilia Kalos in 1923 in New York to poor Greek immigrant parents George and Litsa, became used to her family mistreating her long before the men in her life did the same.

She was singing arias from Carmen by the time she was ten and her mother continually pestered the young Callas to perform for others.

In 1937, her marriage disintegrating, Litsa moved back to Athens with Maria and her older sister Jackie. 

During World War II, she helped shelter British officers — while prostituting herself to Italian and German soldiers to make ends meet, and pressured her daughters to do the same.

Although Jackie gave in, says Spence, Maria managed to persuade the occupying soldiers to pay her simply for singing for them — she had started her musical training in Greece aged 13 — but she ‘never forgave’ her mother.

In 1945, Callas returned to the U.S. to be reunited with her father and to audition — successfully — for the Metropolitan Opera in New York.

After she became a star, her mother, who had always favoured the slim, pretty Jackie over Maria, tried to emotionally blackmail her famous daughter by threatening suicide and leaking stories to the Press about being abandoned.

Her father, who had opened a pharmacy in New York, also shamelessly sponged off his daughter, once even pretending to be dying. 

By the time Aristotle Onassis left Callas for JFK’s widow Jackie Kennedy in 1968, above, his relationship with Callas was so toxic that he once hit her in the face in front of horrified guests, shouting: ‘You’re only good for f***ing. And you’re not even good for that any more.’

But then, despite her imperious, tantrum-filled behaviour as a diva — once ripping up her entire wardrobe the night before a dress rehearsal — Callas was vulnerable to those who showed her affection. ‘With kindness, people can get anything from me, can make me foolish,’ she claimed.

Spence says Callas was ‘always searching for love her parents failed to provide’. She had hoped that she would find that with her husband Giovanni Battista Meneghini, who has been portrayed as the one decent man in her life, but, Spence says, he was also highly predatory.

Callas was 23 and so penniless she couldn’t even afford a coat when she met him at an opera festival in Verona where his brother-in-law, the festival’s official doctor, was on the lookout for pretty singers to direct the ageing businessman’s way.

Despite him being 27 years her senior, the couple married in 1949 and he is credited with loving her and nurturing her career. However, Spence says Callas ‘always wanted to retire and have a baby’ but her husband kept her working, ‘swindling her for years’ as her agent.

He ferreted much of the money away in Swiss bank accounts or used it to pay off his debts. When she discovered what he had done, she described him as her ‘pimp’.

‘My husband is still pestering me after having robbed me of more than half my money by putting everything in his name since we were married,’ she wrote in one letter. ‘I was a fool . . . to trust him.’

He also cheated on her in the bedroom, seducing a string of young women sopranos aged 19 or 20, although Spence discounts whispers that he and Maria never consummated the marriage.

It’s not surprising, perhaps, that Callas traded him in for the wolfishly charming Onassis, an inveterate womaniser who claimed he approached every woman as a potential mistress.

They first met at a ball in Venice in 1957 where Callas found him physically unappealing and unnervingly over-attentive. He pursued her with bucketloads of flowers signed ‘The Other Greek’. Callas didn’t try to put him off, admitting she was ‘happy to be pursued by a man no longer young but still predatory, still sexy, still stalking’.

Their relationship wasn’t consummated, says Spence, until the summer of 1958 when Callas and Meneghini joined Sir Winston Churchill and his family for a fateful three-week cruise on the lavish Onassis yacht, Christina, hosted by the tycoon and his beautiful wife Tina.

The gin palace is now of course notorious for its bar stools upholstered with the foreskins of minke whales so that Onassis could tell his female guests: ‘Madame, you are sitting on the largest penis in the world.’

Churchill’s family loathed the shameless Callas, particularly when she fed the ageing statesman ice cream with a spoon. Her diva behaviour had now reached unbearable levels, with her writing to friends: ‘I like travelling with Winston Churchill. It relieves me of some of the burden of my popularity.’

Once freed of their respective spouses, Callas soon came to see the real Onassis, who returned her slavish devotion with a mixture of contempt, violent anger and lack of interest. He continued to see other women — including Jackie Kennedy’s sister Lee Radziwill.

‘It’s not difficult to be swept off one’s feet. Living with the consequences, that’s the hard part,’ Callas later observed. 

‘People think it’s a great love story,’ says Spence of the Onassis-Callas relationship, but points out that Onassis once ‘almost killed [Callas] from hitting her so hard’.

The singer would shrug off the violence — always followed by gifts of jewellery. ‘She said it was part of his character and she felt so privileged that he could be himself around her,’ says Spence, shocked.

She did whatever he wanted, says her biographer, describing in her book how Callas ‘accompanied him to strip shows, and at his request, wore nothing but her diamonds in bed.’

Callas was already on the path to drug addiction before becoming embroiled with Onassis. In New York, she had met the infamous Max Jacobson, known as Dr Feelgood, who treated celebrities with injections to increase their stamina. 

Unfortunately, his ‘vitamin shots’ were laced with amphetamines and methamphetamines, and were ‘highly addictive’. While she also seemed addicted to Onassis, he played on her insecurity, especially about her weight, so she was ‘like an anxious schoolgirl’ around him.

She has magnetic energy: The star is seen here in 1969

While Spence believes Callas’s prima donna behaviour was in part explained by her frustration at being betrayed by so many around her, she admits that didn’t necessarily excuse it.

Callas could be ruthless to people who got in her way, notably her great soprano rival, Renata Tebaldi, whose voice she was said to have compared to Coca-Cola, while describing her own as champagne.

Although Callas dismissed reports of their 1950s rivalry as media invention, Spence says her unpublished letters — especially one in which she described Tebaldi as ‘as nasty and as sly as they come’ — say otherwise.

By the time Aristotle Onassis left Callas for JFK’s widow Jackie Kennedy in 1968, his relationship with Callas was so toxic that he once hit her in the face in front of horrified guests, shouting: ‘You’re only good for f***ing. And you’re not even good for that any more.’

And yet less than a month after he married Kennedy on his private Greek island Skorpios, he was pleading to see Callas again. She relented after he threatened to drive his Rolls-Royce through her gates.

‘Going to her bedroom, he undressed and got into bed, but she threw him out,’ writes Spence, adding that ‘momentarily, she had the strength to resist him’. She didn’t on subsequent occasions.

Callas would go on to have an affair with the tenor Giuseppe Di Stefano, with whom she recorded many operas, but had to cope with having to share his affections with his family.

As her voice declined, Callas retreated to her Paris home, addicted to pills, and spending her days watching TV and eating ice cream, with her sister Jackie for company.

Her last years, says Spence, were a ‘tortuous routine of loneliness, introspection and regret’. She died of a heart attack in 1977 aged only 53.

The biographer tracked down a neurologist who was treating her before her death and who revealed that Callas had long suffered from dermatomyositis, an inflammatory disease that affected the central nervous system and caused progressive muscle weakness.

Back in the 1950s, however, doctors had dismissed her as a hypochondriac.

If properly treated, says Spence, she wouldn’t have had to turn to the sleeping pills that devastated her life and nor would she have lost her singing voice, ending her career prematurely. ‘Her life was full of tragedy,’ she adds.

Onstage, she was La Divina — but, offstage, she was the eternal victim.