Fr. De Smet's involvement with what was to become
St. Mary's Mission
began during the 1823-24 trapping season when several Iroquois trappers for the Hudson Bay Company remained among the Salish (Flathead) tribe. They were adopted into the tribe and married the Salish women.
The Iroquois, having been introduced to Christianity some two hundred years earlier, told stories about the white men who wore long robes and taught about God.
Between 1831 and 1839 the Salish and the neighboring Nez Perce sent four delegations to St. Louis to obtain a "black robe" to live among them and teach the things which the Iroquois had referred to. The last delegation, comprised of two Iroquois adopted into the Salish tribe was successful and the Indians were promised that a "black robe" would be sent to them.
March 27, 1840 Fr. De Smet set out from St. Louis on his maiden trip to the Rocky Mountains. His assignment, based on the Indian delegation's request for a priest, was to determine whether or not it was feasible to establish permanent missions in the remote areas of the American west. It was decided that one member of the delegation (Lefthand Peter - Peter Gaucher) would travel ahead to relay the good news to the Salish people that a "black robe" was coming. A second member, Young Ignace, would wait at Westport, Missouri Territory (to become Kansas City) and accompany the missionary.
Peter Gaucher arrived at the Salish camp on Eight Mile Creek in the Bitterroot Valley at about the time Fr. De Smet was departing St. Louis. The news he imparted that a "black robe" was coming created joy and excitement among the tribal members. A detail of ten warriors was sent to meet the priest and provide an escort. The chief and remaining tribal members were to follow.
Having met up with Ignace in Westport, Fr. De Smet obtained supplies and horses and then joined a caravan of the American Fur Company. The party of about 40 members left Westport on April 30, 1840 - their destination was the American Fur Company rendezvous on Green River (Wyoming). Two months later, on June 30th, the travelers arrived at their destination. Fr. De Smet was surprised to find the ten warriors awaiting him to act as guides to the main Salish camp. On Sunday, July 5, Fr. De Smet celebrated Mass for the gathering of trappers, traders and Indians which became known as
"The Prairie of the Mass".