Roman Catholic missionary services in Idaho began on Sunday July 10, 1840, in Teton Valley, followed by a mass held near here at Henry's Lake on July 23. Pierre J. DeSmet, a Belgian Jesuit leader, accompanied a Pend Oreille-Flathead band on their way northwest to their homeland. Climbing a mountain here, along streams "descending from dizzy heights, leaping from rock to rock with a deafening noise," he invoked divine thanks for his successful tour into Idaho and Montana.