The Diocese of Boise () is a Latin Church ecclesiastical territory or diocese of the Catholic Church in the northwestern U.S., encompassing the entire state of Idaho. It is led by Bishop Peter F. Christensen, whose seat is the Cathedral of St. John the Evangelist in Boise. The diocese is a suffragan diocese in the ecclesiastical province of the metropolitan Archdiocese of Portland. History Eighteenth and nineteenth century The first Catholics to arrive in the territory that would eventually become the Diocese of Boise were French-Canadian fur trappers in the mid-eighteenth century. That remained the sole Catholic contact in the area until 1815, when 19 Iroquois migrated into Idaho from eastern Canada. These Iroquois had the rudiments of Catholic belief, and apparently spoke of the need for "black robes" to show the way to heaven. Thereafter, for the next twenty-five years, members of the Nez Perce and Flathead tribes made four journeys to St. Louis, Missouri, attempting to recruit a priest for their communities. Their efforts bore fruit when, in 1840, Father Pierre-Jean De Smet, S.J., a Belgian missionary, was appointed to minister to them. The first recorded Mass in Idaho was thus celebrated by Fr. De Smet on 22 July 1840 at Henry's Lake. Fr. De Smet's Jesuit order constructed the first Catholic church in Idaho, built in 1843 along the St. Joe River (near the present-day town of St. Maries) under the leadership of Father Nicholas Point, S.J.. The mission was later moved to banks of the Coeur d'Alene River. The church, named after the Sacred Heart, is most commonly known as the Cataldo Mission. It is the oldest building in Idaho. Until 1862, Catholicism in Idaho remained limited to the tribes of Native Americans in north. However, a gold rush began in 1862 that brought tens of thousands of people to the Boise basin, including a large number of Irish Catholics. President Abraham Lincoln created the Territory of Idaho in 1863, and Pope Pius IX followed up five years later in 1868 by declaring Idaho an apostolic vicariate. At that time, both the territory and the apostolic vicariate included the current state of Idaho and the western portions of Montana and Wyoming. Louis Aloysius Lootens, a native of Belgium a priest of the Archdiocese of San Francisco, was named the first Vicar Apostolic of Idaho, being consecrated as such in the old St. Mary's Cathedral on August