Winnie Madikizela-Mandela, the anti-apartheid leader and second wife of Nelson Mandela has died on Monday, her assistant confirmed with Times Live. She was 81.

She passed away after a battling “a long illness, for which she had been in and out of [the] hospital since the start of the year,” her spokesman Victor Dlamini said in a statement, according to multiple reports.

“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,” the statement said.

Madikizela-Mandela championed for the end of apartheid in South Africa and became a controversial figure once her marriage to Nelson Mandela ended in 1996.

In 1991, she was convicted of kidnapping and an “accessory to assault” for her role in the death of a teenager at the hands of her bodyguard, according to BuzzFeed News. 

Following the controversy, which she avoided jail time for, she became the leader of the African National Congress Women’s League in 1993 and was elected in South Africa’s parliament in 1994 and served under her former husband as deputy minister of arts, culture, science, and technology, according to BuzzFeed.

In 2016, she was honored for her efforts to free the South African people by receiving the National Orders’ Order of Luthuli in Silver.