Cause of death: heart attack
Marguerite Yourcenar (UK: , US: ; French: [maʁɡ(ə)ʁit juʁsənaʁ] ; born Marguerite Antoinette Jeanne Marie Ghislaine Cleenewerck de Crayencour; 8 June 1903 – 17 December 1987) was a Belgian-born French novelist and essayist who became a US citizen in 1947. Winner of the Prix Femina and the Erasmus Prize, she was the first woman elected to the Académie Française, in 1980. In 1965, she was nominated for the Nobel Prize in Literature.
Source : Wikipedia