 Together with the venerable St. Mary's Cathedral Basilica in Galveston, Sacred Heart serves more than 1.2 million Roman Catholics in the Archdiocese of Galveston-Houston.In 1847, Pope Pius IX established the Diocese of Galveston for the 20,000 Catholics who lived in the new state of Texas.This new diocese covered an area as large as France and was served by one bishop and ten missionary priests.