Sacagawea

Lewis and Clark hired Toussaint Charbonneau and his wife Sacagawea, a Lemhi Shoshone woman, as interpreters and guides to accompany them on their expedition. They hired them when they discovered that Sacagawea spoke Shoshone, which would be helpful when they needed help of Shoshone tribes. She soon proved her worth when the expedition tried to trade for horses to cross the Rocky Mountain and used her to interpret. The tribe's chief was Sacagawea's brother Cameahwait. He agreed to let them buy horses and provided guides to lead them over the Rocky Mountains. Besides her role as interpreter and guide, Sacagawea's mere presence with the expedition showed their peaceful intent, as it was a token of peace.