In 1806, Bishop John Carroll laid the cornerstone of the new Basilica (from a stained glass window at the Basilica of the National Shrine of the Assumption of the Blessed Virgin Mary shown at right).
On November 6, 1789, Pope Pius VI appointed Fr. John Carroll of Upper Marlboro, Maryland, the first Catholic bishop in the United States and selected Baltimore as the seat of the first diocese. When Bishop Carroll was consecrated on August 15, 1790 at Lulworth Castle in England, there was only one Catholic church in Baltimore, St. Peter’s, located on the north side of Saratoga Street between Cathedral and Charles Street.
St. Peter’s, resembling more a middle-class residence than a church, served as Bishop Carroll’s pro-Cathedral until his death in 1815, although by 1806 he laid the cornerstone of the present Basilica of the National Shrine of the Assumption of the Blessed Virgin Mary at Cathedral and Mulberry Street. Estimates vary on the number of Catholics in Maryland at the end of the Revolution, but the figure usually cited is 6,000. By Bishop Carroll’s death, the Catholic population was 10,000.