Sacheen Littlefeather, the Native American activist who declined Marlon Brando's Oscar for The Godfather on his behalf in 1973, has died aged 75.
The actress, who had breast cancer, died on Sunday, the Academy announced.
Her death comes two weeks after the organisation honoured her at a ceremony in Los Angeles, publicly apologising for her treatment at the Oscars.
Littlefeather, of Apache and Yaqui heritage, was booed while speaking on stage at the event 50 years ago.
Dressed in full Apache attire during the first Oscars to be televised around the world, the Californian, born Maria Cruz, explained on Brando's behalf that he would not accept his best actor gong for the mafia movie in order to protest against the treatment of Native Americans by the film industry and to bring attention to the Wounded Knee protests.
In 1973, several hundred locals, together with radical activists from the American Indian Movement (AIM), poured into the nearby village of Wounded Knee in South Dakota to protest government abuse.
The protest resulted in a violent stand-off with federal agents that went on for 71 days.
'Speak the truth'
"I went up there, like a proud Indian woman with dignity, with courage, with grace, and with humility," she remembered at the recent event.
"I knew that I had to speak the truth. Some people may accept it. And some people may not."