A Brief History
A Brief History Part I: Early Years (c.520) - Reformation (1536):
The early Irish church was primarily monastic and did not have dioceses in the modern sense. There were several monasteries in the Dublin and Wicklow area but Glendalough (Glenn Dá Loch, the glen of the two lakes), founded by St Kevin in the sixth century was one of the most important. As a diocesan structure began to take shape in the early Irish church, the area around Dublin was considered part of the diocese of Glendalough.
The city of Dublin was founded around 841 by the Vikings and it was the Hiberno-Norse king of Dublin, Sitriuc (the first Christian king of the city), who, visiting Rome in 1028, formally established the diocese of Dublin and its cathedral, Christ Church, under its first bishop, Dúnán or Donat. The early bishops of Dublin were trained as Benedictines in England, and from Bishop Gilla Pátraic to Bishop Gréine, each swore canonical obedience to the archbishop of Canterbury. The diocese of Dublin therefore remained separate from the Irish church until it was incorporated, along with Tuam in 1152, and elevated to an archbishopric alongside the already established Armagh and Cashel.
The second Dublin Archbishop, a former abbot of Glendalough and later the patron saint of Dublin, Laurence O’Toole, saw in the arrival of the Anglo-Normans, who filled the positions with loyal subjects of the crown as the Irish occupants expired. The dioceses of Dublin and Glendalough were unified after the death of the last bishop of Glendalough (as a separate diocese), William Piro in 1214. The unification of the two dioceses was confirmed by Pope Honorius III in 1216.
One of St Laurence O’Toole’s successors, Henry of London (archbishop from 1212-1228) raised the status of a collegiate church, St Patrick’s, outside the city walls to that of a cathedral, leaving Dublin with the unusual situation of having two medieval cathedrals in the one city. The situation became complicated and litigious resulting in difficulties in the appointment of archbishops which required the ratification of both cathedral chapters, seeing as each proposed their own candidate. A ‘composicio pacis’, or peace agreement was made in 1300 by which both were recognised as diocesan cathedrals, and this would last until the 1870s.