Saint Thomas Catholic Church, located in Potosi, Wisconsin, is a
testament to the enduring faith and resilience of its congregation. Its history is
intertwined with the growth and development of the community it serves. The church's story begins in 1836, when Father Samuel Mazzuchelli, a
Dominican priest from Milan, Italy, arrived in Potosi. Despite the challenges of
the American frontier, Father Mazzuchelli was determined to serve the
spiritual needs of the diverse community, which included native tribes,
immigrant settlers, miners, and farmers. Father Mazzuchelli united the local Catholics to form the St. Thomas Parish and built a log cabin church where the St. Thomas parking lot now stands. His tireless efforts laid the foundation for the church's growth and development. In 1847, under the leadership of Father James Causse, the first resident pastor, the current St. Thomas Church was built. This brick structure, which cost $11,000 at the time, is the oldest continuously used church in Wisconsin. Father Mazzuchelli's influence extended beyond the establishment of the parish. He designed and built over 24 churches, including St. Thomas Church. His contributions to the community were recognized in 1993 when Pope John Paul II declared him Venerable, initiating the process of
recognizing him as a saint in the Roman Catholic Church.

Saint Andrew Catholic Church, nestled in the heart of Tennyson,
Wisconsin, is a symbol of the enduring faith and unity of its congregation. Its
history is deeply intertwined with the growth and development of the
community it serves. The story of Saint Andrew Catholic Church begins in the mid-1840s, when German-speaking immigrants established their parish in what is now known as Tennyson. Father Andrew Tusch, the founding pastor, played a pivotal role in the establishment of the church in 1846. In 1847, just a year after the establishment of the parish, the first Saint Andrew School was built. This marked the beginning of a long-standing tradition of Catholic education in the community. The construction of the present Saint Andrew Church took place between 1874 and 1877 under the leadership of Father Nicholas Thill. This beautiful structure, built in 1875, continues to serve as a place of worship for the local community. 

Samuel Mazzuchelli, born in Milan, Italy, Nov. 4, 1806, descended from a family of merchants and bankers. At age 17, Samuel entered the Dominican Order of Preachers against his father's wishes and at a time when the Order was struggling.

Father Mazzuchelli, at the age of 22, came to the American frontier in 1828, and was assigned by Cincinnati Bishop Edward Fenwick to be missionary priest of the whole of the Northwest Territory.

Father Mazzuchelli traveled the Northwest Territory, from the Great Lakes to the Mississippi and beyond. He traveled by horseback, canoe, and foot, and served native tribes and new immigrant settlers, miners, and farmers, as well as political leaders, Catholics, and Protestants

Many of the local parishes he established exist today, and he designed and built over 24 churches, including our St. Thomas Church.  In 1836 when, Father Samuel Mazzuchelli, O.P. came to Potosi, he united area Catholics to form St. Thomas Parish. He built a log cabin church where the St. Thomas parking lot now lies.

In 1993, Pope John Paul II declared Father Mazzuchelli Venerable. This began the process of someday possibly recognizing Father Samuel as a saint in the Roman Catholic Church.