 In 1835, Pierz departed for the missions of the United States after years of being inspired by the published letters of the Slovenian missionary priest, and future Bishop, Father Frederic Baraga, who worked in present-day Upper Michigan and Wisconsin.Pierz arrived in the Diocese of Detroit on September 16, where he presented his credentials to Bishop Frederick Rese.As Lake Superior, had already frozen, Father Pierz was prevented from immediately joining Father Baraga in Wisconsin and was assigned to the Ottawa Indians of Cross Village.