Located across the street from another historical landmark, St. Alphonsus Church, St. Mary's Assumption Church is one of the finest churches in New Orleans and Louisiana. It was built in 1860 in the Baroque style, featuring a large tower, ornamental exterior brickwork, and a baroque interior that includes fine wood carvings. The church was one of three (the other two were St. Alphonsus and Notre Dame de Bon Secours) that comprised the once thriving St. Alphonsus Parish, which was also called the ecclesiastical square during its heyday. All three churches were built by the Redemptorists (a Catholic order) to serve the growing Catholic population in the 1840s and 1850s. St. Mary's primarily served the German community; St. Alphonsus served the Irish community and Bon Secours served the French community. St. Mary's continues to serve as an active church. St. Alphonsus is now a cultural center and Bon Secour was dismantled some time ago. St. Mary's is listed on the National Register of Historic Places and is a National Historic Landmark.
The Redemptorists arrived in New Orleans somewhat by chance. In 1842, Remptorist priest Father Peter Czackert happened to be passing through New Orleans. The bishop at the time, Bishop Antoine Blanc, felt that Czackert's arrival was heaven sent and asked him to minister to the German immigrants who had began to arrive in 1840. Czackert and later another priest, Father Joseph Kundek, who was Croatian, led the effort to build the first St. Mary's Church. This one was eventually replaced by the current one in 1860.