In the Hell on Wheels Handbook, AMCtv.com reveals the story behind Eva's chin tattoo.

In 1851, the Oatmans -- a pioneer family from Illinois -- embarked to California in search of gold and a Mormon paradise. Tragedy struck when they encountered some Yavapai Indians at the Gila River in present-day Arizona. The Yavapais attacked the family with clubs and knives then ransacked their supplies. Olive Oatman, 14, and her sister Mary Ann were spared as the rest were left to die. "I distinguished the groans of my poor mother," Olive later wrote. Lorenzo, 15, also survived, despite a bloody blow to his head.

The Yavapais enslaved Olive and Mary Ann for a year -- they "took unwarranted delight in whipping us on beyond our strength," Olive wrote -- but eventually traded the girls to the Mohave Indians for two horses, three blankets, vegetables and beads. Life with the Mohaves was a major improvement. They treated Olive as one of their own, bestowing her with Mohave names like "Aliutman," "Olivino" and "Spantsa." (Though Olive never admitted to it, historians believe she was sexually involved with tribe members.)

During her four years as a Mohave initiate, Olive received a blue chin tattoo -- Mohaves considered tattoos to be a form of I.D. in the afterlife. "[They] pricked the skin in small regular rows on our chins with a very sharp stick, until they bled freely," Olive wrote. The sticks were then dipped in weed juice and blue stone powder which was then applied to the pinpricks on the face.

Olive seemed content with her new life, so when authorities from Fort Yuma, CA, finally tracked her down and negotiated a trade with the Mohaves, Olive cried -- as did her adopted family. (Mary Ann had already died from illness.) When Olive arrived at Fort Yuma, she became an instant celebrity. Newspapers around the country called her a hero and a victim -- the Los Angeles Star described her as "a pretty girl" who'd been "disfigured by tattooed lines on the chin." In ensuing years, Olive talked to packed houses about her experiences. Her account of her captivity grew increasingly negative toward the Mohaves, which leads some to believe that she may have been suffering from Stockholm Syndrome -- a paradoxical psychological phenomenon wherein hostages express empathy and have positive feelings towards their captors.

In the 1880s, the "tattooed captive" became a popular circus theme. "Their stories turned, provocatively, on the notion that people of color could transform whites into people of color," Margot Mifflin writes in The Blue Tattoo: The Life of Olive Oatman. Olive eventually married a rancher and moved to Texas. She died of a heart attack in 1903.