The Jim Crow era. The great migration of blacks from Southern to Northern cities. The Harlem Renaissance. The Civil Rights Movement. The 20th century’s horrors, triumphs, stagnations and progress are the stuff of history books now. But Sarah “Sadie” and A. Elizabeth “Bessie” Delany witnessed the entire epoch firsthand—and played a part in it, by establishing successful careers in teaching and dentistry in an era when few women held professional jobs.

“We’re not anything special,” Sadie insisted at first, when journalist Amy Hill Hearth interviewed the two centenarian sisters for a newspaper article. Hearth begged to differ. The African American sisters, born in 1889 and 1891, were two of 10 children born to Henry and Nanny Delany. Henry was born a slave in 1858, and later grew up to be the first African American bishop in the Episcopal church and vice principal of St. Augustine’s School in Raleigh, North Carolina. Nanny, too, worked at St. Augustine’s as a matron. Sadie and Bessie grew up on the school’s campus and later moved to New York City to pursue educations and careers. After retiring, they moved to Mount Vernon, New York, where Hearth met them. Even after 10 decades of life, their memories, wits and sense of humor endured. The New York Times published Hearth’s major feature about the sisters on September 22, 1991—when Sadie was 102 and Bessie had just turned 100.

But Hearth—a journalist who shines a light on untold stories and unknown people—sensed an opportunity to create a longer, more thorough portrait of the sisters’ lives and soon signed a book contract with Kodansha America. Over the course of many months, she interviewed the sisters in their home, digging into topics as light as the women’s favored breakfast foods, and as heavy as race. “What we did was very daring,” Hearth, who is white, later told The New York Times. “We agreed not to worry about each other. White people are terrified to talk about race with a black person because they are afraid of saying the wrong thing.” The Delanys possessed not only pristine memories of their lives, but also the ability to communicate their stories to people—like Hearth—who were much younger and had different life experiences. They provided historical context for their anecdotes, making them accessible to a wide audience, and creating a narrative that, when woven together by Hearth, serves not only as a personal story, but also as a sweeping chronicle of a century-long swath of American life. Having Our Say: The Delany Sisters’ First 100 Years, co-authored by all three women, was published in 1993. The book spent 113 weeks on The New York Times’ Bestsellers list, and the Delanys— who had always lived simply skyrocketed to fame. Interview requests soon grew overwhelming and the book found an immediate spot in high school curricula. Hearth, who had become close to the sisters, grew protective of them, screening their interview requests and, when First Lady Hillary Rodham Clinton came to visit, convinced the Secret Service not to disrupt the elderly women’s routine too much.

The sisters, like many successful authors before them, capitalized on their fame and quickly collaborated with Hearth to produce another book: The Delany Sisters’ Book of Everyday Wisdom. This book contains a mix of homespun advice for living (“Exercise, because if you don’t, by the time you’re our age, you’ll be pushing up daisies”) and insights into the life of a centenarian (“But when you get to be our age, everyone keeps expecting you to die. That gets mighty annoying!”).

Meanwhile, Emily Mann, artistic director of McCarter Theatre Center in Princeton, New Jersey, adapted Having Our Say into a play. The stage adaptation premiered at McCarter under Mann’s direction in early 1995, then moved to Broadway, where it ran for 317 performances. The Delanys traveled from Mount Vernon to Manhattan to see the play; officials seated them in a private box so they wouldn’t be bothered by crowds. But word got around that the sisters were in attendance, and when the play ended, audience turned and applauded the Delanys. Sadie, then 105, and Bessie, 103, who had spent decades of their lives forced to the back of the bus, were now the toast of Broadway.

A few months later, on September 26, 1995, Bessie Delany passed away at her home in Mount Vernon, with her sister, other family members, and Hearth by her side. She had recently turned 104. Although Sadie was beset by grief—until death did them part: the Delany sisters had spent only a few months of the past 104 years living separately—she nonetheless refused to wallow or be idle. Once again, she worked with Hearth on a book, this one entitled On My Own at 107: Reflections on Life without Bessie. The book explores her journey from anguish over the loss of her sister to finding renewed purpose, with Bessie’s flower garden as her inspiration. Sadie, who was old enough to have clear memories of the 19th century, spoke of the possibility that she might see the 21st. She narrowly missed it, passing away in her sleep on January 25, 1999 at 109 years old. For 19 years since, African American history has marched on without the Delany sisters. America elected a black president. Racial tensions simmered and boiled over. A new generation came of age. Though the sisters’ tales of segregation, lynchings and perseverance may seem faded, they inform our present—and may motivate us to build a more just future.

Buy tickets and learn more about Having Our Say here.