Winnie Mandela has passed away at the age of 81. South African media confirmed the news on Monday afternoon. Her family will has released a statement on Monday, stating that Mandela had been in and out of the hospital since the beginning of the year battling an undisclosed illness.

Born Nomzamo Winifred Madikizela-Mandela, the former first lady married Nelson Mandela in 1959, just four years before he was sentenced to life imprisonment for treason. They had two children together.

Mandela herself was detained for her involvement in the anti-apartheid movement. In 1969 she was sentenced to 18 months in solitary confinement after being charged under the Suppression of Communism Act of 1950.

Mandela held several government positions throughout her lengthy career, including head of the African National Congress Women's League and Deputy Minister of Arts, Culture, Science and Technology.

She's being remembered by many on social media. Archbishop Emeritus Desmond Tutu, Idris Elba, Joy-Ann Reid and more have shared heartfelt messages honoring her legacy.