Maria Callas (1923-1977) is often hailed as one of the greatest sopranos of the 20th century. She’s best known for her performances in the operas Medea, Tosca and La Traviata, and when TIME put her on the cover of the Oct. 29, 1956, issue, the magazine dubbed her “the undisputed queen of the world’s opera.” But Maria, the Netflix biopic starring Angelina Jolie as Callas out today (Dec.11) does not take place at the height of her career.