Galveston-Houston, an outgrowth of the first Catholic diocese in Texas, has for more than 150 years steadily grown in Catholic population, although it has diminished considerably in land area. When it was established in 1847 as the Diocese of Galveston, the see included all of Texas as well as parts of what is now Oklahoma, New Mexico, Kansas, Colorado, and Wyoming-an area of almost 360,000 square miles, home to some 20,000 widely scattered Catholics. Twelve priests assisted the first bishop, Jean Marie Odin (1847–61), in a diocese that held ten or so established churches and a convent of Ursuline Sisters. The early clergy, including Odin, became known as "saddle priests" because of their extensive travel on horseback. Odin's greatest challenge was to secure the resources needed to build the diocese. He made several visits to Europe and Canada to recruit priests and religious. He also solicited funds from Catholics overseas; such organizations as the French Association de la Propagation de la Foi, the Austrian Leopoldinen-Stiftung, and the Bavarian Ludwig Missionsverein contributed substantially to the growth of the Catholic Church in Texas in the nineteenth century.
Claude Marie Dubuis (1862–81), long a Texas missionary, replaced Odin upon the latter's appointment as archbishop of New Orleans. Dubuis remained in Galveston when the diocese underwent the first of many divisions; the diocese of San Antonio and the vicariate apostolic of Brownsville were established in 1874. Dubuis returned to France in 1881, leaving behind a diocese that, though now covering only half of Texas, had grown to include 30,000 Catholics, 43 priests, 107 women religious, 50 churches and chapels, 17 schools, and 1 hospital.
Succeeding Dubuis was Nicholas Aloysius Gallagher (1882–1918), Galveston's first United States-born prelate. Though Gallagher began service in 1882, he did not receive the title of bishop of Galveston until 1892. He brought more religious communities to serve in Texas, and the continued growth led to yet another division in 1890, when the diocese of Dallas was formed from the dioceses of Galveston and San Antonio. In 1886 Gallagher opened in Galveston what is reported to be the first Catholic school for black students in Texas.
Christopher Edward Byrne (1918–50) became the fourth bishop of Galveston in 1918 and made native clergy a priority. He ordained more than 200 priests, one-third of whom were Texans. He also expanded church ministry among Mexican Americans and African Americans. In 1947 the University of Saint Thomas opened in Houston under the direction of the Basilian Fathers. The same year, the diocesan centennial celebration scheduled for April 29–30 was cancelled because of the Texas City disaster of April 16.
Bishop Wendelin Joseph Nold (1950–63), a native Texan, transferred the ecclesial offices to Houston and renamed the diocese Galveston-Houston. Nold's tenure saw almost fifty new parishes established, and Houston gained three new secondary schools and a new chancery. John Louis Morkovsky (1963–85) succeeded Nold, but Nold retained his title. As apostolic administrator and coadjutor bishop, Morkovsky established a broad range of commissions to oversee diocesan services and growth. A diocesan newspaper, the Texas Catholic Herald, began publication in 1964. The diocese also assumed charge of a mission in Guatemala. Morkovsky officially assumed the title of bishop of Galveston-Houston in 1975, retired in 1985, and was succeeded by Joseph A. Fiorenza.
In 1966 the diocese of Beaumont was established from a segment of Galveston-Houston. Over the years the dioceses of San Antonio and Dallas had also undergone subdivision. Thus in the late 1980s Texas had one archdiocese, San Antonio, and thirteen suffragan dioceses (Galveston-Houston, Dallas, Corpus Christi, El Paso, Amarillo, Austin, San Angelo, Brownsville, Beaumont, Fort Worth, Victoria, Lubbock, and Tyler), making the state the biggest of all Catholic provinces worldwide. Also in the late 1980s Galveston-Houston, once the only diocese in Texas, included but ten counties (Brazoria, Fort Bend, Galveston, Grimes, Harris, Madison, Montgomery, San Jacinto, Walker, and Waller) and western segments of Liberty and Chambers counties-an area of 8,983 square miles. In the diocese 407 priests, 599 sisters, 220 permanent deacons, and 17 brothers served a Catholic population of 667,058. The diocese had 148 parishes, 13 missions, and 3 hospitals, as well as 1 university and 8 secondary and 46 elementary schools, with a total enrollment of 16,444.