Rarely can there have been someone who was called to greatness and yet failed that calling as decisively as Winnie Madikizela-Mandela, who has died aged 81 after a long illness. In Harlem they called her “the Queen of Africa”, in South Africa “the Mother of the Nation”. In the end she was neither, her reputation irrevocably mired in murder and fraud.

The main part of her story unfolded over nearly four decades of marriage to Nelson Mandela, during much of which he was imprisoned along with other leaders of the African National Congress. She remained active in the freedom struggle, though subject to persecution and shorter periods of imprisonment. When Nelson was released in 1990, she was by his side, but her actions before then, and her inability to establish a sound political role after his election as president in 1994, left her a marginalised figure despite her great personal following.

Born in the famously rebellious district of Pondoland in the Eastern Cape, Nomzamo Winifred Zanyiwe Madikizela was one of nine children – six of them daughters – of two teachers and devout Methodists, Columbus Madikizela and his wife, Gertrude.

Winnie’s biographer Emma Gilbey (The Lady: Life and Times of Winnie Mandela, 1993) records that she was a rebel in her own right from an early age. By ancestry and circumstance she was an explosive mixture. Her mother, who had red hair, blue eyes and “very pale skin”, seems to have been of mixed race and suffered for it at the hands of her mother-in-law, who tormented Gertrude as a mlungu, a white person.

Described as a tomboy, Winnie was, it seems, something more than that. Her first name, Nomzamo, translates as “she who must endure trials” – which, while it was true of her later life, may be said to have applied to those who had to suffer her early behaviour. In a horrific account of one childhood fight, details of which are attributed to members of the family, Gilbey recounts how, “no longer content to rely on fists, feet, or even sticks, Winnie had secretly fashioned a vicious weapon by taking a tin and driving a nail through the bottom of it.

“When fighting, Winnie whipped out the tin and slugged her sister in the mouth, ripping through her lip with the nail and tearing into the flesh of her mouth. The wound bled copiously and needed stitches. The thrashing Gertrude gave Winnie, in one of their final run-ins, affected Winnie for the rest of her life.”

Despite the beating, Winnie appears to have nursed considerable affection for her mother and was devastated by her death – possibly of tuberculosis – as she was previously by the death of her eldest sister. Their deaths, when she was about 10 years old, seem to have shaken her belief in a Christian god. But they also brought her closer to her father, a remote figure in her childhood. He started encouraging her reading, for which she developed a voracious appetite.

The Madikizela family was not poor, at least by local standards, but for most families in South Africa’s rural areas life was a struggle and Winnie, it seemed, did not fail to appreciate her relatively good fortune. As a contrast to the more violent side of her nature, Gilbey describes an incident when Winnie learned of a local girl who was staying away from school because she had no suitable clothes to wear. Winnie promptly gave her one of her own dresses. “Columbus was so proud of his daughter’s act of selflessness that, when he found out what she had done and why, he rushed out to buy two more dresses – one for the girl and one for Winnie”.

It was a part of her character that took her from school to social work, and she enrolled at the Jan Hofmeyr School of Social Work in Johannesburg in 1953. Blossoming into a great beauty in her early 20s, she was courted by such figures as the princely Kaiser Matanzima, a relative of Nelson Mandela who was later to be reviled as a Bantustan leader and a “sell-out” in the liberation struggle.

Described by Gilbey as a “remarkably effective and dedicated social worker”, Winnie was horrified to hear from Pondoland that, in line with tribal tradition, her father was planning to give her away in marriage to the son of a local chief. Coincidentally, there was a man in Johannesburg who was facing a similar arranged marriage back in the Transkei. There was somehow an inevitability about Winnie and Nelson meeting, setting in motion one of history’s great and yet tragic love stories.

They met at a delicatessen. By this stage Winnie had met and become a friend of Adelaide Tsukudu, then fiancee and later wife to Oliver Tambo. The three of them were driving through Soweto when they stopped off to get a bite to eat. Tambo spotted Nelson in the deli and introduced him to Winnie. Shortly afterwards, Nelson phoned her and asked her out.

“I was, of course, petrified,” Winnie recalled. “He was much older than me and he was a patron of my school of social work. We had never seen him, he was just a name on the letterheads; he was too important for us students to even know him.” Winnie was 23, Nelson nearly 40. By all accounts they were passionately in love.

They married in June 1958, in Pondoland, Nelson paying lobola (bride price) in the African tradition. They had to abandon plans for a reciprocal ceremony at Mandela’s home in the Transkei because he had to return to Johannesburg, where he was one of the accused in the so-called Treason trial. Winnie famously took the top tier of the wedding cake back to Johannesburg, intending that it should be eaten when they had a chance to visit her in-laws together. They were never to eat the piece of cake.

Quickly falling pregnant, Winnie threw herself into political work. Arrested while taking part in an anti-pass law demonstration, she nearly lost her first child in prison, haemorrhaging badly. Released after a fortnight, she found that she had been fired by the Soweto hospital where she worked.

She suffered another blow when her father accepted a position in the Transkei “cabinet”, as minister of agriculture and forestry. He was perceived as selling out to the “bantustan” system of black homelands, and so conniving in apartheid. Winnie demanded that he resign, but he refused. There were several attacks on his home, which was eventually burned down, and Winnie’s grandmother was assaulted.

In 1961, following the collapse of the Treason trial, Mandela went underground and was captured the following year. In 1964, at the conclusion of the Rivonia trial, he and seven other ANC leaders were sentenced to life imprisonment. The sentences left Winnie virtually the only well-known face of the ANC outside prison. She had difficulty in fulfilling the role.

Winnie was personally more militant than the ANC. Her political position was closer to the “Africanist” traditions of Robert Sobukwe and the Pan Africanist Congress. As combative as always, she had several physical altercations with the security branch. She was also lonely and scandal quickly began to attach itself to her name. She was cited in a divorce action as the lover of a young black journalist; a male photographer was found hiding under her bed during a police raid; and she became involved with a young man working at the US Information service.

Winnie suffered her first major spell of imprisonment in May 1969, having been arrested, supposedly for political agitation, but more likely for simply being the wife of Nelson Mandela. Her treatment by police was appalling. Held for 17 months, most of it in solitary confinement, she was interrogated and kept awake for up to five days at a time. Fainting, hallucinating and passing blood in her urine, she landed up in the prison hospital suffering from malnutrition. She recognised the brutalising effect the experience had on her, telling a television interviewer many years later: “I knew what it is to hate.”

Gilbey says Winnie also suffered from paranoia as a result of her prison experience, seeing criticism as “personal betrayal” and her critics as “traitors, spies, informants and sell-outs”. At the trial in 1970 of the so-called “22 detainees”, the accused wore cardboard numbers on string around their necks. When a complacent and arrogant Afrikaner prosecutor rose and addressed Winnie by her number, she retorted that she was not a number, that her name was Winnie Mandela, and she should be addressed as such. It was a display of spiritual strength in adversity that observers never forgot. All the detainees were eventually freed, the charges against them dismissed.

In 1977 the state subjected her to internal exile, banishing her to a shack in the town of Brandfort, in the Orange Free State, more than four hours’ drive from her home in Soweto. The story of her Brandfort years was one of hardship, suffering, loneliness and courage. The police kept her under intense, open surveillance to a degree which suggested that persecution, not surveillance, was the intention.

Concerned by the impact on her younger daughter, Zinzi, by then aged 16, and on whom she depended for company, but who seemed to be close to a breakdown, Winnie bravely sent the girl to stay with a friend, Helen Joseph, in Johannesburg. Her elder daughter, Zeni (Zenani), had married into the Swaziland royal family, so Winnie was leaving herself alone but for the ever-watching police.

At the same time the Brandfort ordeal seemed to be wearing her down, and there were reports that she was drinking heavily there. There were also a number of violent incidents in which she was allegedly involved, including an assault on a nine-year-old child for which she was prosecuted, but acquitted.

In 1985, amid speculation about her husband’s release, her banning order was relaxed and she was able to return to Soweto. Shortly afterwards she delivered a bellicose speech, famously declaring that “with our boxes of matches and our necklaces we shall liberate this country”, in reference to the hideous way in which township residents dealt with suspected collaborators by burning them alive using a tyre and petrol. The speech was to haunt her: years later she would still find herself being challenged by the media about it.

But after Nelson’s release it was to emerge that during a prison meeting at the time he had approved of her comment. Winnie, who presumably remembered her husband’s approval, made no attempt to publicise it, although with his virtually unchallengeable reputation it would have taken much of the heat off her.

In 1989 Winnie’s reputation was damaged beyond redemption, even despite Nelson’s intercession, when the Stompie Moeketsi scandal broke. On 27 January the news of Stompie’s disappearance and the uproar in Soweto surrounding it broke in the Guardian in London and the Weekly Mail in Johannesburg. A few hours later two youths walked into the surgery of Dr Baker Abu Asvat and shot him dead.

As the facts began to emerge about Stompie’s disappearance and death and Asvat’s murder, suspicion of Winnie’s involvement in both hardened into a damning indictment. Stompie, it transpired, was suspected of being a police informer and had been badly beaten up by members of the Mandela United Football Club, which acted as her personal bodyguard, with Winnie either taking part, or at least having knowledge of it. Realising the boy was in extremis, she had called in Asvat, who found him either dying, or dead. This made Asvat a potential witness in a capital case against Winnie. The next day he was dead.

What has become apparent in retrospect is that the two murders did not occur in isolation, but rather opened a noxious can of worms. It is perhaps sufficient to say that, after her death, Winnie’s reputation will suffer just as much from the shadow of the murdered 14-year-old boy as it did in her lifetime. The relevance of the murder of Asvat, a witness to the boy’s death, lies in the fact that in those days murderers were still hanged. The possibility was that Asvat alive could have meant Winnie dead – an icon of the liberation struggle on the scaffold. The potential repercussions were unimaginable.

But time was on Winnie’s side. It was becoming increasingly obvious that Mandela’s release was imminent, particularly after President PW Botha’s stroke and the succession of the reformist FW de Klerk. Even more important matters were at hand than two township murders, particularly after that glorious moment on Sunday 11 February 1990, when Winnie and Nelson walked hand in hand through the gates of Victor Verster prison.

It was a moment of triumph for Winnie, and she had at least a taste of power in those early days of her husband’s freedom. She also had a taste of state power when Mandela and the ANC, reasoning that she was too popular a member of the organisation to be ignored, appointed her deputy minister of arts, culture, science and technology in South Africa’s first majority rule government. She lasted 11 months before Nelson fired her for unauthorised travel abroad amid general allegations of fraud. Despite behaving as if she were above the law that had treated her so badly for so long, she managed to avoid imprisonment.

There seemed to be some self-destruct mechanism at work in her and her post-1990 triumph was not to last long. After disclosures of more affairs had further sapped her reputation, she was finally brought to trial in the Stompie case in 1991, the year she was elected to the ANC national executive. She was originally charged with murder, assault and kidnap, but after the murder charge was dropped she was convicted of the other two charges and sentenced to six years. On appeal the assault charge was dismissed and she was fined R15,000 on the kidnap charge in 1992, when she resigned all her ANC posts, including her parliamentary seat.

She bounced back in 1993, when she was elected president of the ANC Women’s League, taking up her short-lived post. In 1996 Nelson obtained a divorce from her and married Graça Machel in 1998. But she clung on to the connection with the nation’s supreme hero and his name, re-establishing a kind of closeness not long before his death, and she was present at his funeral alongside Machel.

Meanwhile, she had been re-elected to the Women’s League leadership, which she retained until 2003, when she was again accused of fraud, this time of a funeral fund. Given a suspended sentence of three and a half years, she once more won her appeal. Again she bounced back, returning to the ANC national executive on the strength of topping the party poll in 2007.

Her reputation may have been badly dented several times, but her popularity among the African majority clearly remained broad and deep. She was irrepressible; the voters thought her indispensable. She was re-elected to parliament two years later, having risen close to the top of the ANC’s list of candidates headed by Jacob Zuma.

In 2008 she took up the cause of immigrants who had come under attack in widespread riots arising from unemployment and social deprivation. She publicly apologised to them, railing against xenophobia, and attacked the ANC government for its housing policy failures.

When Nelson Mandela died at the end of 2013, she became involved in unseemly and bitter disputes involving their two daughters and other relatives over his estate and legacies. She went to court in 2014 to lay claim to the Mandela home in the Eastern Cape, on the grounds that their customary or tribal marriage had never been dissolved, unlike the civil one that had ended in 1996. The case was dismissed in 2016, and her health went into decline at the start of this year.

She is survived by her daughters.

• Nomzamo Winifred Zanyiwe Madikizela-Mandela, political campaigner, born 26 September 1936; died 2 April 2018

• David Beresford died in 2016