In November 1815, a slave known only as Anna jumped from the third-floor window of a tavern in Washington, D.C. The 24-year-old was then sold for $5 by interstate slave traders from Georgia and separated from her husband and four children. Though she broke her back, Anna survived. The story was reported widely at the time; in many instances, it was used as fodder for the abolitionist movement. But following the incident, history lost track of Anna.

Thirteen years later, a slave named Ann Williams filed a petition for her freedom—and won. It turned out to be Anna. But for 200 years, “no one knew that she had sued for her freedom,” William G. Thomas III told The Atlantic. Together with director and animator Michael Burton and writer Kwakiutl Dreher, Thomas produced the short film Anna, based on Williams’s story. It premieres on The Atlantic today.

The filmmakers stumbled upon Williams’s lawsuit in the National Archives in Washington, D.C. while researching the case files of slaves who petitioned for their freedom. “We began putting the pieces of her story together,” Thomas said. “We were moved by the resilience of the human spirit. Anna's story gives us an unflinching look at slavery—it shows us how enslaved people made a way out of no way.”

“We wanted to tell Anna’s story from her perspective and from the perspective of an enslaved person,” said Dreher, “avoiding common tropes and bringing the viewer into her everyday life.” Dreher adapted a screenplay based on Anna’s words in several written accounts, and Burton compiled a database of images and contextual information for each scene, containing references of local buildings, structures, tools, utensils, clothing, and hairstyles. Burton rotoscoped the film, a labor-intensive animation process that involved “first filming the actors in costume, then tracing over every other frame of the footage with acrylic or digital paint, then overlaying each of the animated characters onto a background painting,” he said. “I wanted to create a distinct style that drew on early 19th -century etching techniques to create a kind of lifelike version reminiscent of that earlier style.” Nine animators worked over the course of a year and a half to animate each scene.

In the antebellum South, many hundreds of slaves brought freedom suits. Among the most famous cases is 1857’s Dred Scott v. Sandford, in which the U.S. Supreme Court ruled that African Americans were not and could never be citizens of the United States and denied Missourian slave Scott his freedom.

Williams is believed to have won her case due to a violation of the Maryland Act of 1796, a legal provision designed to prevent enslavers from using Maryland as a way station in the transatlantic slave trade. She won freedom in court for herself and her children in 1832.