The first chapel measured 25x33, with two galleries in order to accommodate the entire tribe. Father DeSmet made a trip to Fort Colville of the Hudson Bay Company and returned with supplies to tide them over the winter, plus wheat, oats, potatoes and garden seeds for the first crops.
The news of the Black Robes' arrival spread, and within a short time Indians from many tribes came to visit. The following year, a larger church, 30x60, was built a few hundred yards east of the river. Following a trip to Fort Vancouver on the west coast, from where he brought into Montana the first cattle, swine and poultry, Father DeSmet returned to St. Louis. After seeing off a group of helpers to travel overland to St. Mary's, he left for Europe to seek recruits and funds for the new mission area in the Northwest.
One of his recruits was a true renaissance man,
Father Anthony Ravalli, S.J.
an Italian, who arrived at St Mary's in November 1845. In addition to being a Jesuit priest, he was Montana's first physician, surgeon and pharmacist. He was an architect, an artist and sculptor. He built the first grist mill and saw mill. Religion classes were held twice a day. There were classes in reading, writing and arithmetic taught in the Salish language. There was a band that played numbers by German and Italian composers. The Indians were taught to plow, plant, cultivate, irrigate and harvest crops and to tend cattle, sheep, pigs and poultry.
A larger church was under construction in 1846. Before it's completion, problems with the Salish's traditional enemies, the Blackfoot, forced what was intended to be a temporary closure of the Mission. By terms of a Conditional Bill of Sale in November 1850, John Owen, a former army sutler, bought the improvements for $250.00. Should the Jesuits return within two years the mills and fields would revert to them. When they were unable to return by the designated time, the Jesuits sent word to burn the church to save it from desecration. The former mission site became
Fort Owen, a trading post.