At Waiilatpu west of Walla Walla, Marcus and Narcissa Whitman established a Presbyterian mission in 1836 on Cayuse land after being welcomed by the Cayuse. From 1843 to 1847 it became an important Oregon Trail stop, as increasing emigrant traffic deepened Cayuse fears that white settlement would take their land. During a devastating measles outbreak in November 1847, about half of the local Cayuse died while more white settlers survived. On November 29, 1847, Marcus and Narcissa Whitman and eleven others were killed, and forty-seven residents were taken hostage, events that helped spark the Cayuse War and the organization of Oregon as a U.S. territory.