Saint Louis Cathedral is in the French Quarter of New Orleans, Louisiana, United States, on the Place John Paul II (French: Place Jean-Paul II), a promenaded section of Chartres Street (rue de Chartres) that runs for one block between St. Peter Street (rue Saint-Pierre) on the upriver boundary and St. Ann Street (rue Sainte-Anne) on the downriver boundary. It is located next to Jackson Square and facing the Mississippi River in the heart of New Orleans, situated between the historic buildings of the Cabildo and the Presbytère.
Three Roman Catholic churches have stood on the site since 1718, when the city was founded. The first was a crude wooden structure in the early days of the French colony. As the French were Catholic, their church was prominently located on the town square. Construction of a larger brick and timber church was begun in 1725 and was completed in 1727. Along with numerous other buildings, the church was destroyed in the Great New Orleans Fire (1788) on Good Friday, March 21, 1788. The cornerstone of a new church was laid in 1789 and the building was completed in 1794. In 1793 Saint Louis Church was elevated to cathedral rank as the See of the Diocese of New Orleans, making it one of the oldest cathedrals in the United States. In 1819, a central tower with the clock and bell was added.
Enlarging the building to meet the needs of the growing congregation had been pondered since 1834, and J. N. B. de Pouilly was consulted to design plans for a new building. De Pouilly also designed St. Augustine Church in Tremé, the first church building dedicated as a parish church outside the French Quarter. (The Mortuary Chapel on North Rampart had been dedicated in 1827 as a chapel, and St. Vincent de Paul was established in a little frame church in 1838 but not dedicated.) On March 12, 1849, the diocese contracted with John Patrick Kirwan to enlarge and restore the cathedral, using De Pouilly's plans.
These specified that everything be demolished except the lateral walls and the lower portions of the existing towers on the front facade. During the reconstruction, it was determined that the sidewalls would have to be demolished also. During construction in 1850, the central tower collapsed. De Pouilly and Kirwan were replaced. As a consequence of these problems and reconstruction, very little of the Spanish Colonial structure survived. The present structure dates primarily to 1850. The bell from the 1819 tower was reused in the new building and is still there today.During the renovation, St. Patrick's Church served as the pro-cathedral for the city.
According to wikipedia