Marcus was a physician and a Protestant missionary. In 1836 he and Narcissa, together with a group of other missionaries, joined a caravan of fur traders and traveled west, establishing several missions as well as their own settlement. Located in the Walla Walla Valley on the northern end of the Blue Mountains near the present day city of Walla Walla, Washington, it was in the territory of both the Nez Percé and the Cayuse Native American tribes. The latter called it Waiilatpu (Why-ee-lat-poo, the 't' is half silent), which means "place of the rye grass" in the Cayuse language. Marcus farmed and provided medical care, while Narcissa set up a school for the Native American children. In the early days, life was peaceful at the Whitman Mission.