In 1758, Mary Jemison was living with her family in western Pennsylvania. A group of Shawnee natives and French soldiers captured her during the French and Indian War. Jemison was fifteen years old at the time of her capture. Her parents and three of her younger siblings were killed. A group of Seneca natives purchased Jemison and took her with them to the Ohio Country. The Senecas adopted the teenager and gave her the name Dehgewanus, meaning "Two Fallen Voices."
Dehgewanus learned the ways of the Seneca and married Sheninjee, a member of the Delaware natives. They had two children, but only one survived. Soon after the second child was born, Dehgewanus and Sheninjee began a trip to Sheninjee's homeland along the Genesee River in New York. Sheninjee died along the way, but Dehgewanus continued on the trip. The New York Senecas made a home for her at Little Beard's Town. Dehgewanus married again, this time to a Seneca, and had seven more children. She had become a member of the Seneca and remained in New York for the rest of her life. Dehgewanus died in 1833 at the age of ninety. Like many other Native American captives, Mary Jemison preferred life with Native Americans rather than a return to her previous lifestyle.