Crowds celebrate Winnie Mandela's life at Soweto memorial service

The memorial in Soweto comes ahead of a funeral service to be held on Saturday.

Madikizela-Mandela died in a Johannesburg hospital on April 2 at the age of 81, after what her family said was a long illness. She was known as the "Mother of the Nation" because of her struggle against white minority rule in South Africa.

Singing echoed around Orlando Stadium in Soweto as the mourners waited, some dancing as they sang, for the service to start. Many were clad in the black, green and gold of the ruling African National Congress political party, some in T-shirts with an image of Madikizela-Mandela.

The Soweto Gospel Choir led those gathered in the singing of the national anthem as proceedings began.

Madikizela-Mandela was married to Nelson Mandela for 38 years, including the 27 years he was imprisoned on an island near Cape Town.

A family statement announcing her death described her as "one of the greatest icons of the struggle against apartheid" who had "sacrificed her life for the freedom of the country."

"She kept the memory of her imprisoned husband Nelson Mandela alive during his years on Robben Island and helped give the struggle for justice in South Africa one of its most recognizable faces," the statement said.

A longtime stalwart of the ANC, Madikizela-Mandela was a member of South Africa's parliament at the time of her death.

One of the last official visits she received was from current South African President Cyril Ramaphosa, who went with her to Soweto township last month to encourage people to register to vote in next year's presidential election.

Following her death, Ramaphosa praised Madikizela-Mandela as "an advocate for the dispossessed and the marginalized" and "a voice for the voiceless."

"Even at the darkest moments of our struggle for liberation, Mam' Winnie was an abiding symbol of the desire of our people to be free," Ramaphosa said in a statement. "In the midst of repression, she was a voice of defiance and resistance. In the face of exploitation, she was a champion of justice and equality."

Born in 1936 in what is now known as Eastern Cape province, Nomzamo Winifred Madikizela was the daughter of a history teacher.

As a 22-year-old social worker, she married Nelson Mandela in 1958, and stood by him in the years following his 1964 conviction and life imprisonment for sabotage and conspiracy to overthrow the government.

Madikizela-Mandela led an international campaign calling for his release.

Outside Africa, Madikizela-Mandela was known largely because of her ex-husband, but in South Africa she was the mouthpiece and face of the bitter struggle against the racist regime.

Although Madikizela-Mandela helped usher in a new, more equitable South African political system during her lifetime, she was also entangled in a number of scandals over the years.