Pierre Dorion was a Frenchman from Canada. About 1780, he came to work as a fur trader along the Missouri River. He married a Yankton woman. They had three sons. In 1806, Lewis and Clark hired Dorion to work with the Indians again. The explorers were then on their way home. Dorionís sons were also fur traders and interpreters. In 1811, the oldest son would guide a different group to the Pacific Ocean. These travelers were called the Astorians.