St. Ambrose Cathedral is a historic building located in downtown Des Moines, Iowa, United States.

[4] At the time, Des Moines was part of the Diocese of Dubuque, which covered the entire state of Iowa.

[7] Bishop Clement Smyth, OCSO named him the vicar general of the diocese, and he cultivated many contacts in state government.

Nicholas Sassel established St. Mary's, no longer extant, to serve the pastoral needs of the city's German community.

[8] Flavin had seen a model for a high altar designed by Tiffany Studios displayed at the 1893 Columbian Exposition in Chicago.

[11] St. Ambrose Church was chosen to be the cathedral of the Diocese of Des Moines when it was established by Pope Pius X on August 12, 1911.

[13] In the 1920s Bishop Thomas Drumm and St. Ambrose pastor Francis O'Connell executed a renovation of the cathedral plant in the 1920s.

A new 18-foot (5.5 m) reredos was created for the high altar's original mensa by Conrad Schmitt Studios of Milwaukee, and used for the first time at Christmas 1944.

Another large-scale renovation of the cathedral was begun in the 1970s by Bishop Maurice Dingman out of a desire for a better liturgical environment, and because the building was in need of repairs.

Maur Burbach, OSB, of St. Pius X Monastery in Pevely, Missouri was named liturgical consultant and Rambusch Decorating Company of New York City was hired to do the design work.

The cathedral's interior painting and decorating was subsequently and completely renovated again starting fall 1996, and finished in the spring of 1997, by Don A. Wendt, Ecclesiastical Studios & Sons of Greenwood, Missouri.

In a spirit of ecumenism, Bishop Dingman offered the use of St. Ambrose Cathedral for the episcopal consecration of the Rt.

[15] The cathedral was designed in the Romanesque Revival style that is similar to the historic churches found in southern France.

The entranceway is flanked on the right by a tall bell tower, which is composed of five sections that are differentiated by a change in the stonework, and topped by a pyramid-shaped spire.

[2] Flanking the left side of the entrance is a structure that is ⅔ the height of the larger church and is articulated by a semicircular projection that is topped by a conical roof.

The altar, ambo and chair in the chapel were used by Pope John Paul II during a Mass he celebrated at his historic visit to Living History Farms just outside Des Moines in 1979.

[1] It is a three-story structure that is composed of both stone and brick and is designed in the Romanesque Revival style to match the cathedral next door.