When Rosa Parks was a little girl in rural Alabama, she would stay up at night, keeping watch with her grandfather as he stood guard with a shotgun against marauding members of the Ku Klux Klan.

Klansmen often terrorized black communities in the early 1900s, and Parks’s grandfather, Sylvester Edwards, the son of a white plantation owner, had their house boarded up for protection.

But Parks longed for a showdown.

“I wanted to see him kill a Ku-Kluxer,” the renowned civil rights leader wrote in a brief biographical sketch years later. “He declared that the first to invade our home would surely die.”

They sounded like hard words for the small, bespectacled woman who is most famous for refusing to give up her seat to whites on an Alabama bus in 1955.

[See the arrest report from police on the arrest of Rosa Parks.]

But a cache of Parks’s papers set to be unveiled Tuesday at the Library of Congress portrays a battle-tested activist who had been steeped in the struggle against white violence since childhood.

The trove, parts of which were unknown to historians, also shows Parks as a woman devoted to her family, especially to her mother and husband, Raymond, for whom she kept her hair in long braids even after he died.

The material is part of the collection of Parks’s belongings that was purchased by the Howard G. Buffett Foundation in August and deposited with the library in September on a 10-year loan, the library said.

Parks died in Detroit in 2005 at the age of 92, famous for a solitary act of defiance that helped launch the modern civil rights movement and etched her name in the annals of history.

The material opens to researchers Wednesday, Parks’s birthday, and a small section of it will be on display in the library’s Jefferson Building from March 2 to March 30.

Other parts will join the library’s civil rights exhibit, which runs through Sept. 12.

Maricia Battle, curator with the prints and photographs division of the Library of Congress, poses for a photograph as she holds a photo of Rosa Parks that is part of a Rosa Parks archive. (Matt McClain/The Washington Post)

The artifacts displayed at a media preview last week included Parks’s tiny Bible; a snapshot of the Tuskegee, Ala., house where she was born in 1913; and letters to her mother, Leona, and her husband.

“Parks, my dear husband,” she wrote him in 1957, while she was working in Virginia and he was home in Alabama. “I miss you so very much and wish you were here.”

During an earlier absence, in 1956, her mother wrote to her that she was fine, “but Parks is about as usual when you are away.”

There are little-known photos of her husband, who was also an activist and who quietly supported her and weathered death threats as she traveled the country.

One shot of him is a wallet-size photo she cropped to carry around with her.

There are other photos — of her father, who deserted the family when she was a toddler, and of several unidentified people.

One is an old postmortem photo of an elderly man in a coffin.

And there are pages and pages of writing that record her thoughts about the plight of African Americans, bits of her biography and prayers.

She wrote on anything she could find: the back of a utility company envelope, the back of a civic program, the front and back of a church program, pages torn from a notebook, the stationery of a department store that fired her.

“These were the things she was not able to part with,” said Maricia Battle, a curator of photography at the library. “These are the things that were most dear to her.”

“It’s family,” Battle said. “It’s her husband.” She never remarried after he died in 1977. They had no children.

“Raymond was the love of her life,” Battle said. “You can just see it when you go through and look at the images here. It’s just wonderful.”

Battle said she had never seen a picture of Raymond Parks before. Along with the wallet photo, the collection includes an image of the couple sitting together at an NAACP dinner in the early 1950s.

Much of the material dates from the time before Rosa Parks became famous.

One fragment, perhaps a draft of a letter, is written on the stationery of Montgomery Fair, the department store where she had worked.

She speaks of the 1955 murder of the black teenager Emmett Till, who was killed in Mississippi after allegedly flirting with a white woman.

“This case could be multiplied many times in the South,” she wrote in pencil. “In my lifetime I have known Negroes who were killed by whites, without any arrests or investigations. . . . It is the custom to keep such things covered up.”

The collection also illustrates the financial impact of her bus action.

“She loses her job,” said Margaret McAleer, senior archives specialist. “Her husband loses his job. They were poor, working class to begin with. They descend into deep, deep poverty.”

Another intriguing fragment is the brief, undated biographical sketch, written on a few pages torn from a notebook.

In it, she tells of the Klan menace in her rural community of Pine Level, Ala.

“KKK moved through the country, burning negro churches, schools, flogging and killing,” she wrote.

Her grandfather, who was tall, thin and “very caucasian in appearance,” had long, white hair that she loved to comb.

“He would stay up to wait for [the Klansmen] to come to our house,” she wrote. “He kept his shotgun within hand reach at all times. . . . The doors and windows were boarded and nailed tight from the inside. I stayed awake nights keeping vigil with grandpa.”

Adrienne Cannon, an African American history and culture specialist at the library, said parts of the handwritten sketch do not appear in her published autobiography, “Rosa Parks: My Story.”

The book is Parks’s “public image,” Cannon said.

The sketch is “Rosa with her hair down,” she said. “She’s 6 years old . . . waiting for Grandpa to kill a Ku-Kluxer. This is the real deal. This tells you how she had the strength and determination to do what she did.”

Parks became famous on Dec. 1, 1955, when she boarded a public bus in Montgomery on her way home from work and refused to move from a seat to allow whites to sit.

What followed was the historic 380-day black boycott of Montgomery buses, a U.S. Supreme Court decision desegregating the city’s public transportation and the modern civil rights movement.

But Parks, in a way, was trapped by history — “frozen in the bus seat,” Battle said.

She was the heroic, fed-up seamstress.

“It seemed like her life started and stopped with the bus,” Battle said.

But that was not the case.

“She didn’t stop there,” Battle said. “She continued. She worked with organizations. She started her own institute to honor her late husband. She worked with kids all over the world.”

“People are more than that one little thing that you often think of them,” she said. The collection shows “the breadth of who she really was.”