The Archdiocese of Galveston-Houston is blessed with two Cathedrals.
The Diocese of Galveston was established in 1847 and St. Mary Cathedral was dedicated on November 26, 1848.
With the growth of the city of Houston, Pope John XXIII designated the city of Houston to be an episcopal city in 1959. Thus the Diocese of Galveston was henceforth to be known as the Diocese of Galveston-Houston. This did not change the status of the city of Galveston as an episcopal city established in 1847, the first such city in the state of Texas.
With the elevation of Sacred Heart Parish to a Co-Cathedral, it became co-equal in rank with St. Mary Cathedral Basilica in Galveston. With this designation, an episcopal chair was also installed in Sacred Heart Co-Cathedral. Full episcopal ceremonies could then be celebrated in Houston, as well as in Galveston.