Lewis and Clark brought Sacagawea with them on their expedition because she was a Shoshone woman who had been kidnapped and later married to a French-Canadian fur trader named Toussaint Charbonneau. Sacagawea's knowledge of the land and her ability to speak Shoshone and Hidatsa language made her an important asset to the expedition. She also served as a translator and mediator with Native American tribes they encountered along the way. Additionally, Sacagawea's presence helped to convey a message of peace and cooperation to the Native American tribes, as she was a woman and a mother traveling with a group of men.
