Watch VoirFilms. On April 15, 2000, on the day ten years after Greta Garbo's death, a cardboard containing about fifty letters was opened at the Rosenbach Museum in Philadelphia, USA. The letters were written by Greta Garbo and addressed to her friend Mercedes de Acosta. She was a playwright and screenwriter. But in Hollywood, she came to be best known for her love affairs, with some of the biggest female stars of the film and theater.