Nobody would have imagined that the young Milanese Carlo Gaetano Samuele Mazzuchelli was destined to leave his mark on the rivertowns of the Upper Mississippi River.

He was born November 4, 1806, in Milan, Italy, to a wealthy merchant family with deep roots in the Lombardy region. The Mazzuchellis lived on the stately Piazza Fontana, in the shadows of one of the world’s great houses of worship, the Milan Duomo, and within walking distance of the abandoned Dominican priory of Santa Maria delle Grazie, which is the home of Leonardo da Vinci’s masterpiece The Last Supper. The young Mazzuchelli was educated at the Collegio di Sant’ Antonio, a private academy in Lugano, Switzerland.

A political career seemed inevitable, but, at the age of 17, he shocked his family when he announced that he felt called to a religious vocation. A short time later he joined the Dominican Order and gave up a familiar and privileged life for the alien world and privation of the American frontier.

At 22, he endured a grueling, seven-month journey to America, arriving in Cincinnati in 1828 with only a crude understanding of English. After his ordination in 1830, he was assigned to serve Native Americans and fur traders in the outposts of the Northwest Territory: Mackinac Island, Green Bay, and Sault Ste. Marie. In 1835 his mission shifted to the growing communities in the lead mining region around Galena, Illinois, and Dubuque, Iowa. Father Mazzuchelli arrived just after the Black Hawk War, at a time when thousands of new settlers were streaming into the region in search of riches and a new life. For eight years, he served Catholics in growing communities along the Upper Mississippi River from Prairie du Chien to Fort Madison, Iowa.

During these years, the Mississippi River was his interstate highway. In warm months, Mazzuchelli was a regular passenger on steamboats destined for towns in his ministry or to St. Louis for his annual retreat, often riding gratis because many steamboat captains declined to charge him. In winter, the ice on the Mississippi was usually strong enough to support a man on horseback. In February 1843, for example, Mazzuchelli rode 10 miles across the frozen Mississippi from Fort Madison, Iowa, to Nauvoo, Illinois, to discuss theology with Joseph Smith. Smith, the leader of the Church of Jesus Christ of Latter Day Saints, was assassinated about a year later.

Spring was a much more challenging time for river travel. In his memoirs, Mazzuchelli wrote of a crossing in March 1838, when ice and a poorly chosen boat nearly put an end to his ministry: ” … the drifting ice, more than a foot thick and in masses of enormous size, greatly increased the danger, for if one of these had struck the boat, it would surely have sent it to the bottom… The four passengers were already sitting in the water; the priest and the steersman were kneeling in it -for the boat was only four inches above the surface when, thanks be to God, an island offered a safe refuge.”

Exhausted and ill in 1844, Mazzuchelli returned to Italy for a year to recuperate and visit his family, although his idea of rest was to write a two-volume memoir describing his experiences on the American frontier. His book provided much detail on his architectural legacy, most of which comes from the period when he was based in Galena. While his ultimate purpose was to save souls, he devoted considerable energy to the construction of buildings to serve that aim.

For someone with no apparent training in architecture, his buildings are stout and show a diversity of design influences—Romanesque, Gothic, Greek Revival and Italian Renaissance—and are built of wood, stone or brick. He also knew how to get the most church for the money. Using a combination of salesmanship, donated materials and labor, and his own frugality, he stretched available resources to build churches that were often a little grander than a community could afford. Occasionally, he reached too far, and contributions from other sources were needed to finish construction.

On a bitterly cold February day in 1864, Mazzuchelli responded to an urgent request to visit a seriously ill woman who lived four miles out of town. He went immediately, not dressing properly for the freezing weather. The next day he developed pneumonia, and a week later he died at his rectory in Benton, Wisconsin. He was buried in Benton’s St. Patrick’s cemetery.

This Italian man, born into a privileged world, who chose a life of poverty and service on the American frontier, helped establish the foundations for community life in burgeoning towns of the Upper Mississippi Valley. He has left us a remarkable legacy.

Father Mazzuchelli’s labors and virtues have received more recognition in recent years. Papers claiming miracles associated with him were sent to the Vatican for review a few years ago, which may lead to the pope declaring Mazzuchelli as “blessed”—one step away from sainthood.

Most of the surviving buildings designed by Ma