From the Archdiocese of Hartford Website:
Initially, the first Waterbury Catholics were the mission responsibility of Hartford’s Father James Fitton. Pastoral jurisdiction then passed to the care of New Haven. In 1845, the Catholics rented Washington Hall at the corner of Exchange Place and West Main Street. On November 1, 1847, the mission was created a parish initially under the patronage of St. Peter, with Father Michael O’Neil named first pastor. A vacated Episcopal church was purchased and moved to a location on East Main Street, opening for Mass on Christmas Day 1847. On July 5, 1857, the cornerstone of a new church was blessed and dedicated in December by Bishop Francis P. McFarland. St. Peter’s was renamed to honor the recently proclaimed dogma of the Immaculate Conception. In 1863, the pastor converted the old church into a parochial school, staffed by laymen and women. Father John A. Mulcahy built St. Mary School, dedicated on September 4, 1888 by Bishop Lawrence S. McMahon and staffed by the Sisters of Charity. In 1907, Father William J. Slocum organized the initiative to build St. Mary Hospital, the cornerstone of which was blessed on September 22 by Bishop Michael A. Tierney. Father William McGurk chaired the citywide committee of Catholic clergy and laymen to build Waterbury Catholic High School, which opened in 1926. He also undertook the construction of a new church, which was dedicated on May 20, 1928, by Bishop John J. Nilan.
The Title of Minor Basilica
In 2008, under the pastoral care of Rev. John Bevins the title minor basilica was conferred upon the Church of The Immaculate Conception by the authority of the Holy Father entrusted to the Vatican Congregation for Divine Worship and the Discipline of the Sacraments. The bestowal of the title initiated a very particular bond between the church and the Holy Father and set the church apart in rank from other churches. While the principal church of the Archdiocese of Hartford is the Cathedral of Saint Joseph, where the cathredra is found, the chair of the Archbishop and sign of his teaching office, the basilica ranks after the cathedral as a church of great distinction. The title minor basilica distinguishes the church in rank from the few churches in the world that bear the title major basilica.
Minor Basilica Proclamation
From the office of the congregation for divine worship and the discipline of the sacrament. -February 9, 2008
At the request of His Excellency, the Most Reverend Henry Joseph Mansell, Archbishop of Hartford, in his letter dated December 8, 2006, prompted by the prayers and requests of the clergy and the faithful, the Congregation for Divine Worship and the Discipline of the Sacrament, in virtue of special faculties given by the Supreme Pontiff Benedict XVI, gladly bestows on the parish church dedicated to God in honor of the Immaculate Conception of the Blessed Virgin Mary in Waterbury the title and dignity of a Minor Basilica, with all the laws and liturgical rites faithfully observed according to the Decree:“DE TITULO BASILICAE MINORIS”, promulgated on the ninth of November 1989. Anything to the contrary not withstanding.