Studied and ordained in Rome, Italy on 7 April 1821. Distinguished himself in the study of the Scriptures. Professor of theology at the seminary in Bardstown, Kentucky, where he was an active missionary. Co-adjutor bishop of Philadelphia, Pennsylvania and titular bishop of Arath on 25 February 1830; bishop of Philadelphia on 22 April 1842. In Philadelphia he began the construction of a seminary and of the cathedral of Saint John the Evangelist, started the Catholic Herald, protested against the anti-Catholic Nativist riots of 1844, and helped restore peace to the city in the wake of that violence. Archbishop of Baltimore, Maryland on 19 August 1851. Apostolic delegate from the Vatican. Convened and presided over the First Plenary Council of Baltimore in 1852. He introduced the Forty Hours’ Devotion into the United States in 1853, and in 1854 was appointed by Pope Blessed Pius IX to collect the opinions of the American bishops on the doctrine of the Immaculate Conception; he later attended ceremonies in Rome for the proclamation of that dogma. His literary works include , , and a translation of the Bible with commentary.