Before she was known for her defiant act that catapulted the American civil rights movement into prominence — and placed her at the center of it — Rosa Parks had long been a human rights activist and crusader for social justice.

But the clues to why she was such a passionate activist may come from a handwritten essay, parts of which were released to the Associated Press, detailing her account of an attempted rape at the hands of a white neighbor. The six-page writing is part of a large archive of her personal items sitting in the offices of a New York auctioneer that is expected to be sold off.