[4] The first Catholic presence in present-day Iowa was that of the French Jesuit missionary, Reverend Jacques Marquette.

He traveled down the Mississippi River with the French explorer Louis Jolliet in 1673, stopping briefly at what is now Montrose in southern Iowa.

With the growth of the Catholic population, Bishop Joseph Rosati of St. Louis sent the Belgian Jesuit Reverend Charles Van Quickenborne to the newly founded Dubuque in 1833, where he organized the first parish.

When Fitzmaurice died of cholera in early 1835, Rosatis sent the Dominican Reverend Samuel Mazzuchelli to replace him.

[11] In 1849, with Ireland ravaged by the Great Famine, several Irish Cistercians immigrated to Iowa to build the New Melleray Abbey in Peosta.

In 1863, during the American Civil War, Smyth learned about a branch of the Knights of the Golden Circle (KCG) in Dubuque, a secret paramilitary society with sympathies for the Confederate South.

On April 24, 1866, Pius IX appointed Reverend John Hennessey of Saint Louis as the third bishop of Dubuque.

[citation needed] During Hennessy's tenure, the population of Dubuque exploded as the Milwaukee Railroad opened a maintenance center in the city.

[18][19] In 1878, the Sisters of the Third Order of St. Francis of the Holy Family relocated from Iowa City to Dubuque to staff St. Mary's Orphan Home.

[20][21] Hennessy was a strong proponent of Catholic education, terming public schools as "dens of iniquity" and "gates of hell".

[27] During his tenure as archbishop, John Keane encouraged postgraduate courses and ongoing education for priests, and doubled the faculty and buildings of St. Joseph's College.

[26] To succeed John Keene, on August 11, 1911, Pius X appointed Bishop James Keane from the Diocese of Cheyenne as the next archbishop of Dubuque.

[17] On January 17, 1930, Pope Pius XI named Bishop Francis J. Beckman from the Diocese of Lincoln as archbishop of Dubuque.

Impressed with the Catholic culture he had seen in Europe, Beckman began to collect fine art pieces.

In 1941, the Vatican ordered the creation of a Special Commission on Administration, composed of three American archbishops, to take control of the archdiocese's finances.

[citation needed] On June 15, 1944, Pope Pius XII appointed Bishop Henry Rohlman from Davenport as coadjutor archbishop of Dubuque.

While Rohlman was archbishop, Christ the King Chapel was constructed at Loras College, St. Mary's Home for Children was built in Dubuque, and the number of priests in the archdiocese rose from 290 to 345.

[32] On October 15, 1949, Pius XII named Bishop Leo Binz from the Diocese of Winona as coadjutor archbishop in Dubuque.

[34] He also established the North American Martyrs Retreat House in Cedar Falls, and expanded the archdiocesan branch of Catholic Charities.

[33] John XXIII nominated Bishop James Byrne from the Diocese of Boise to be the next archbishop of Dubuque on March 7, 1962.

[35] On December 20, 1983, Pope John Paul II appointed Bishop Daniel Kucera of the Diocese of Salina as the eighth archbishop of Dubuque.

[40] After Hanus retired in 2013, Pope Francis on April 8, 2013, appointed Bishop Michael Jackels from the Diocese of Wichita as the next archbishop of Dubuque.

Francis appointed Bishop Emeritus Richard Pates from Des Moines to serve as the apostolic administrator, running the archdiocese.

[44] In July 1874, Bishop Hennessy granted Catholic residents of Centralia permission to build St. John the Baptist Church.

Founded in 1891, St. Francis Parish in Balltown is now part of the St. John Baptist de La Salle Pastorate.

Peter and Paul Parish in Sherrill, Iowa, is now part of the St. John Baptist de La Salle Pastorate.

With the influx of German Catholic immigrants to the area, Bishop Loras established the St. William Parish in Sherrill.

[47][46] In 1889, the parish replaced its original wood church with the current brick and stone Romanesque Revival structure.

[46] For over 100 years, the Franciscan Sisters of Perpetual Adoration (FSPA) of La Crosse, Wisconsin, operated the parish school.

Although a large settlement was paid to victims by Archbishop Jerome Hanus in 2006, cases continue to surface and be litigated.