Most students of Pacific Northwest history are familiar with the 1847-48 measles epidemic because of its association with the killing of Marcus and Narcissa Whitman by Cayuse Indians, on November 29, 1847, at a missionary site some four miles west of present-day Walla Walla, Washington. It is also generally known that, prior to the violence, the epidemic had ravaged the Cayuse who then lived near the Whitmans' Waiilatpu Mission. And, finally, it has been widely thought that the disease was brought to the region by American migrants traveling over the Oregon Trail. This relatively well-known story about what has come to be known as the Whitman Massacre is neither complete nor altogether accurate.