Winnie Madikizela-Mandela, a political activist in the fight to end apartheid in South Africa, has passed away at the age of 81.

Madikizela-Mandela, who was the former wife of late South African president Nelson Mandela, passed away at the Netcare Milpark Hospital in Johannesburg, South Africa after a long bout of an undisclosed illness.

"Mrs. Madikizela-Mandela was one of the greatest icons of the struggle against apartheid. She fought valiantly against the apartheid state and sacrificed her life for the freedom of the country," reads a statement from the family (via CNN).

"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 its most recognizable faces."

Dubbed the mother of post-Apartheid South Africa, Madikizela-Mandela became the international symbol of resistance to apartheid while her husband was imprisoned on Robben Island for 27 years.

She also was jailed for her role in the fight for justice and equality for South Africans, but never wavered in her fight against white minority rule in South Africa.

Madikizela-Mandela was married to Nelson Mandela for 38 years and divorce in 1996. They had two daughters together Zenani and Zindzi. Nelson Mandela died in 2013.

Although Madikizela-Mandela was a tireless activist, she also found herself mired in several legal cases. In 2013, Madikizela-Mandela was convicted of kidnapping and in 2003 was found guilty of fraud. In addition, South Africa's Truth and Reconciliation Commission accused her of involvement in horrific human rights abuses during the apartheid era.

Upon hearing the news of Winnie Mandela's passing, music artists such as Chuck D, Estelle, Rapsody and more posted their condolences on social media.

"She lived for everyone, fought for lives and empowered along the way," tweeted Estelle. "RIP to a revolutionary, Winnie Mandela!"

Monch wrote, "Winnie Mandela. Rest In Peace 9/26/36 - 4/2/2018. One can only hope in this lifetime to have an ounce of your strength and courage."

Read more artist's reactions below.

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