On September 18, 1847, Pope Pius IX issued the bull Ad Futuram Rei Memoriam, establishing the Vicariate Apostolic of Brownsville, with the Immaculate Conception Church in that city designated as the cathedral. To commemorate these 150 years, Bishop Daniel E. Flores, along with numerous bishops of Texas and priests of the diocese, celebrates a Mass of Thanksgiving on September 18, 2024, at the Basilica of Our Lady of San Juan del Valle - National Shrine.