"To work with her, you had to really understand how she saw your role, not how you saw it. She had a very clear-cut understanding of her role, and you had to fit into that interpretation. She was so great, [yet] she could not distance herself from a role. It was actually quite terrifying — she would at times actually cry while singing! You must only portray the emotions, not become personally involved. But Maria always became the role. She was such a servant of the text and the composer, she would tear her voice to ribbons to accomplish it!"
January 1, 1970
https://en.wikiquote.org/wiki/Maria_Callas