Saint Mary's Parish was founded in 1855 by the Rev. Francis Xavier Pierz. He celebrated the first Mass in the parish on May 21 in the home of John and Catherina Schwarz. Property was bought for $500 and plans were made for a wood-frame church and a school. In 1856 a Benedictine monk from Saint John's Abbey in Collegeville, Minnesota, became the parish's first pastor and a combination church and school building was built on Eighth Avenue, across the street from the current parish offices. Benedictine nuns from Pennsylvania arrived in 1857 to start the parish school. It was the first school in Stearns County. They lived in a parishioner's attic until John Tenvoorde rented his "entertainment center" for use as a convent. Six years later they moved to Saint Benedict's Monastery in Saint Joseph, Minnesota. After two years they returned to St. Mary's and continued to teach in the school.