The origin of this Cathedral was established on July 20, 1703, by Jean-Baptiste de La Croix de Chevrieres de Saint Vallier, Bishop of Quebec at Fort Louis de la Mobile, the city's first permanent settlement. The Bishop also appointed Father M. Henri Roulleaux de La Vente as Pastor of the first formal church along the Mississippi Valley which extended from the mouth of the Mississippi to Canada.
The missionary zeal of the early Catholic Jesuit priests accompanying Mobile's founders brothers, Pierre Le Moyne, d'Iberville and Jean Baptiste Le Moyne, de Bienville was intrinsic to the religious development of Mobile, Alabama.
The Cathedral Archives preserve the records of Mobile's multicultural and diverse origin. The sacramental records began by the first pastor, M. Henri Roulleaux de La Vente date back to 1704, documenting the first baptisms, marriages, and burials of the French, Spanish, British, Native Americans, Africans, and Creole de Color in Mobile. Many documents are the only reference to eighteenth century African Slaves and are among the oldest on the Gulf Coast.
Some documents are signed by Mobile's founders, Pierre Le Moyne, d'Iberville and Jean Baptiste Le Moyne, de Bienville. The ceremonial placement of the Cathedral's Cornerstone took place in the Catholic Graveyard
on July 19, 1835.