A childhood love of adventure eventually led the Belgian Jesuit priest Father Pierre-Jean De Smet to become a missionary to the Indians of the Rocky Mountains. He traveled throughout the northern Rockies, along the way celebrating the first Catholic Mass in what’s now Wyoming on July 5, 1840, during the Green River Rendezvous. In 1851, members of his party named Lake De Smet for him as they traveled from the Missouri River in present Montana to assist in treaty negotiations with the plains tribes near Fort Laramie.

In August 1856, more than 1,000 Mormon emigrants in the Willie and Martin handcart companies left Florence, Nebraska Territory, with plans of reaching Salt Lake City and the headquarters of The Church of Jesus Christ of Latter-day Saints before winter. Their late start, substandard equipment and lack of sufficient supplies had disastrous consequences when they were hit by winter storms. Hundreds died on the journey across what’s now Wyoming and into Utah. Images of emigrant families pulling handcarts have since become an LDS Church icon of the triumph of faith over adversity.

As the beaver trade waned in the 1830s, so did economic reasons for an American toehold in the Oregon country, still under joint British-American occupancy. Religion shifted the balance of power, however, when American Protestant missionaries crossed the Rocky Mountains with an eye toward converting the tribes of the Northwest. Soon these men brought their wives with them as well. In 1836, Narcissa Whitman and Eliza Spalding were the first Euro-American women to cross South Pass, and these people became the vanguard of American settlement of Oregon.

The Welsh-born Episcopal priest John Roberts arrived in 1883 at Fort Washakie on what’s now the Wind River Indian Reservation in Wyoming, became a friend of the Shoshone chief Washakie, and served the Shoshone and Arapaho people with a loving paternalism well into his old age. John Roberts died in 1949.