He was sent to England where he was consecrated by Archbishop Ralph of Canterbury, but on his return, he was prevented from entering his see by those who wanted Dublin integrated with the Irish hierarchy.
A compromise was reached by which Gregory was recognised as bishop of Dublin, while he in turn accepted the authority of Cellach, archbishop of Armagh, as primate.
"[8] On 20 October 1551, the Protestant Edward VI and the Privy Council of England transferred the Anglican primacy from George Dowdall of Armagh to George Browne of Dublin,[9] as the former opposed the Reformation in Ireland, which the latter advanced by introducing the 1549 Prayer Book and destroying the Bachal Isu, both a Catholic relic and a symbol of Armagh's primacy.
[10] In the 1630s, Lancelot Bulkeley of Dublin argued that Protestant Edward's decree ought to be accepted and Catholic Mary's annulled, but in 1634 the Lord Deputy of Ireland, Thomas Wentworth, felt that without stronger evidence the primacy should remain with Armagh.
[11] The Church Temporalities Act 1833 reduced Tuam and Cashel and Emly from archdioceses to dioceses, leaving no archbishops other than the two primates.
In 1963 Tomás Ó Fiaich and William Conway suggested that the period of Cullen and MacCabe's primacy was the only time during which "the leadership of the Irish Church" was in Dublin rather than Armagh; and the motivation was the necessity of close contact with the Dublin Castle administration in the period after Catholic Emancipation, especially until the controversy over control of education was eased by the Intermediate Education (Ireland) Act 1878 and Royal University (1880).
[19] Since 1885, Irish voting members of the College of Cardinals have been archbishops of Armagh rather than Dublin, except when Desmond Connell was appointed in 2001 ahead of Seán Brady.