[AngelicaDeAlquezar]

La Malinche was the daughter of a powerful Nahua nobleman, and sold to Maya slave-traders after her father died. Her knowledge of both languages (Nahuatl and Maya), then her learning Spanish, made her become a translator to Cortez, who had her baptised with the name of Marina. She had a son with him named Martín Cortez.
Since it's perceived that she could choose sides, she was considered a traitor who supported the conquistadores. She didn't seem to mind changing her name (Malintzin or maybe Malinali) and her religion and took advantage of her privileges, not only as the main translator and negotiator, but also as Cortez' mistress.
Whether she had a choice or if what she did was just for survival is not so clear, but she's the historical icon of treason against the nation and its original values.