 In 1877 he was appointed Titular bishop of Gadara and Auxiliary of Dublin, and on the death of Paul Cardinal Cullen, the incumbent Archbishop, he was chosen in 1879 to be Cullen's successor.Three years later, on 27 March 1882, Pope Leo XIII created him Cardinal-Priest of S. Sabina.His pastoral letter in October 1881 denounced in fierce terms the "No Rent Manifesto" of the Irish National Land League; thus his return from Rome with the "red hat" almost went un-noticed.