|Map of Wisconsin and Upper Michigan in the early Pioneer Days
Wisconsin was at first a missionary territory for French Jesuits. Rene Menard, S.J. is reputed to have been the first Catholic cleric in Wisconsin in 1660. A series of Jesuit missionaries, including Claude Allouez, Claude Dablon, and Jacques Marquette, plied the inland waters of Wisconsin in the company of fur traders establishing mission stations in the extreme north of the state: Green Bay and Prairie du Chien. Conversions of the Indians went on in a piecemeal fashion, although it is difficult to ascertain how many became or remained Catholics.
Jesuit activity waned in the 18th century and eventually ceased when the Holy See suppressed the order in 1765. Wisconsin had only a handful of settlers who sustained their Catholic faith, probably by home devotions. There was a protracted period (c. 1781-1820) when there was no resident priest in Wisconsin.
The reactivation of Catholic life in Wisconsin came as the federal government made land surveys and began to sell parcels of land, opening the way for settlers who began to move into the Old Northwest. In the American Catholic community an independent hierarchy was established in 1789 with its seat at Baltimore. Subsequent ecclesiastical subdivisions of the United States created dioceses at Bardstown, Kentucky and Detroit, Michigan -- Wisconsin fell under all three.
Under the impulse of westward expansion, a second wave of Catholic missionary activity began in Wisconsin in the early 19th century, reflected in the work of Dominicans Samuel Charles Mazzuchelli and Theodore Van den Broeck, secular priest Frederick Baraga, as well as priests from Michigan. The two major Catholic outposts by the 1830s were the cities of Green Bay and Prairie du Chien. But by the 1833 the city of Milwaukee was established and Mass was celebrated in the home of the trader Solomon Juneau by Father Florimond Bonduel. Milwaukee would grow spectacularly as immigration to Wisconsin accelerated in the 1830s and 1840s -- made possible by the extinguishing of Indian claims and federal land surveys. Immigrants from the East and abroad poured into the cities along the coast of Lake Michigan. The growing number of Catholics in the Wisconsin territory led the bishops of the Fifth Provincial Council of Baltimore to petition the Holy See in May, 1843 for the erection of a new diocese in Wisconsin. On November 28, 1843, Pope Gregory XVI issued the decree In Suprema Militantis, officially erecting the new diocese and designating Milwaukee (not Prairie du Chien or Green Bay) as its headquarters. John Martin Henni, a Swiss-born priest of the Diocese of Cincinnati was chosen its first bishop. He was consecrated in March, 1844 and took possession of his See on May 5, 1844. There were about 9,000 Catholics in the entire state and about 14 priests. The Catholic community was a combination of rural and urban elements but was already tending toward an urban identity.