Diocese of Dublin and Glendalough
The United Dioceses of Dublin and Glendalough is a diocese of the Church of Ireland in the east of Ireland. It is headed by the Archbishop of Dublin, who is also styled the Primate of Ireland. The diocesan cathedral is Christ Church Cathedral, Dublin.

Overview and history

Early Christianity in Ireland
The broad Dublin area was Christian long before Dublin had a distinct diocese, with monasteries such as Glendalough as well as at Finglas, Glasnevin, Rathmichael, Swords, Tallaght. Several of these functioned as "head churches" and the most powerful of all was Glendalough. 

In the early church in Ireland, the church had a monastic basis, with greatest power vested in the Abbots of the major communities. There were bishops but not organised dioceses in the modern sense, and the offices of abbot and bishop were often comprised in one person. Some early "Bishops of Dublin," back to 633, are mentioned in Ware's Antiquities of Ireland but the Diocese of Dublin is not considered to have begun until 1038, and when Ireland began to see organised dioceses, all of the current Diocese of Dublin, and more, was comprised in the Diocese of Glendalough.

The Norse Diocese of Dublin
Following a reverted conversion by one Norse King of Dublin, Sitric, his son Godfrey became Christian in 943, and the Kingdom of Dublin first sought to have a bishop of their own in the 11th century, under Sitric MacAulaf, who had been on pilgrimage to Rome.  He sent his chosen candidate, Donat (or Donagh or Donatus),  to be consecrated in Canterbury in 1038, and the new prelate set up the Diocese of Dublin as a small territory within the walled city, over which he presided until 1074. The new diocese was not part of the Church in Ireland but of the Norse Province of Canterbury. Sitric also provided for the building of Christ Church Cathedral in 1038 "with the lands of Baldoyle, Raheny and Portrane for its maintenance."

At the Synod of Rathbreasail, convened in 1118 by Gillebert (Gilbert), Bishop of Limerick, on papal authority, the number of dioceses in Ireland was fixed at twenty-four. Dublin was not included, the city being described as lying in the Diocese of Glendalough, but the Norse Bishops continued, still attached to Canterbury.

The Reorganisation of the Church in Ireland, 1152
Then, in 1151, Pope Eugene III commissioned Cardinal Paparo to go to Ireland and establish four metropolitans, and at a general synod at Kells in 1152, Armagh, Dublin, Cashel, and Tuam, were created archiepiscopal sees. In a document drawn up by the then Archbishop of Tuam in 1214, the cardinal is described as finding both a bishop based in Dublin, who at the time exercised his episcopal office within the city walls only, and "He found in the same Diocese another church in the mountains, which likewise had the name of a city (Glendalough) and had a certain chorepiscopus. But he delivered the pallium to Dublin which was the best city and appointed that the diocese (Glendalough) in which both these cities were should be divided, and that one part thereof should fall to the metropolitan." 

The part of North County Dublin known as Fingall was taken from Glendalough Diocese and attached to Dublin City. The new Archdiocese had 40 parishes, in deaneries based on the old senior monasteries. All dependence upon English churches such as Canterbury was also ended.

The Early Archbishops
The founding Archbishop of the larger Dublin Diocese, consecrated at Lambeth, was Gregory, with the Bishops of Kildare, Ossory, Leighlin, Ferns, and Glendalough reporting to him.

The second Archbishop, from 1161 to 1179, was Saint Laurence O'Toole, previously Abbot of Glendalough, who had previously been elected as Bishop of Glendalough but had declined that office. During his time in office, the presence of the Church grew in Dublin city (by 1170 there were six churches other than the cathedral within the walls) and religious orders from the continent came to Ireland (Augustinians, Dominicans, Franciscans and Carmelites had houses in Dublin, and the great convent of Grace Dieu, near Donabate, was an example of women's religious life and education). As part of this trend, Laurence installed a community of canons to minister according to the Aroasian Rule in the Cathedral of the Holy Trinity, later known as Christchurch. The important house of Abbey of Saint Mary was founded in Dublin at that time, first under the Benedictine Rule, then passing to the Cistercians.

Not only was the Irish Church transformed in that 12th century by new organisation and new arrivals from abroad, but Ireland's political scene was changed permanently by the coming of the Normans and the influence of the English Crown.

Saint Laurence's successor was a Norman, and from then onward to the time of the Reformation in Ireland, Dublin's Archbishops were all either Norman or English.

Merge of Dublin and Glendalough 
In 1185, the Lord of Ireland, John Lackland, granted the merge of the dioceses of Dublin and Glendalough. This was initially without effect as the charter lacked papal approval. When the bishop Macrobius died in 1192, a synod was held in Dublin under the direction of the papal legate Metthew O Enna. William Piro was elected as bishop of Glendalough and remained in office at least until 1212. Robert de Bedford was elected as successor in 1213 or 1214 but he had never the opportunity to take possession of the diocesan seat. Instead, John, now King of England, reissued a grant to join Glendalough to Dublin which was finally approved by Pope Innocent III in 1216 and confirmed by his successor Honorius III in the same year.

Reformation
When the Church in England broke communion with the Roman Catholic Church, the Church of England was established by the state as the established church. Later, by decree of the Irish Parliament, a similar new body became the State Church in the Kingdom of Ireland. It assumed possession of most Church property (and so retained a great repository of religious architecture and other items, though some were later destroyed). The substantial majority of the population remained faithful to the Latin Rite of Roman Catholicism, despite the political and economic advantages of membership in the state church. They were obliged to find alternative premises and to conduct their services in secret. The English-speaking minority mostly adhered to the Church of Ireland or to Presbyterianism. In 1833, the two provinces of Dublin and Cashel were merged. Over the centuries, numerous dioceses were merged, in view of declining membership.

Structure
The united entity comprises 95 parishes, many now operating in unions. The parishes and other religious organisations in diocesan jurisdiction include:

Archdiocese of Dublin
Parishes

 Booterstown (Mount Merrion was United with Booterstown)
 Bray
 Castleknock
 Christ Church Cathedral Group of Parishes (St. Andrew, St. Werburgh with St Mary, St. Michan and St. Paul, and All Saints', Grangegorman)
 Clondalkin
 Clontarf, comprising also Killester for many centuries
 Coolock, in Union with Raheny since 1960
 Crinken
 Crumlin
 Dalkey
 Donnybrook
 Drumcondra
 Dun Laoghaire
 Glenageary
 Holmpatrick (Skerries)
 Howth
 Kill
 Killiney (Ballybrack)
 Killiney, Holy Trinity
 Kilternan
 Malahide
 Monkstown
 Raheny, in Union with Coolock since 1960
 Rathfarnham
 Rathmichael
 Rathmines
 Sandford
 Sandymount
 Santry - St. Pappan's Church
 St. Ann
 St. Bartholomew
 St. George and St. Thomas
 St. Patrick's Cathedral Group of Parishes (St. Catherine and St. James, St. Audoen's)
 Stillorgan
 Swords
 Tallaght
 Taney
 Tullow
 Whitechurch
 Zion

Other entities

 Adelaide and Meath Hospital, Tallaght
 C.O.R E. (City Outreach through Renewal and Evangelisation)
 Church of Ireland Theological College
 CMSI Dublin
 General Synod Education Office
 Irish Church Missions
 Rathdown School
 St. Columba's College
 The King's Hospital
 University College, Dublin
 University of Dublin

Diocese of Glendalough
Parishes

 Arklow
 Athy
 Blessington
 Castlemacadam
 Celbridge
 Delgany
 Donoughmore
 Dunganstown
 Greystones
 Leixlip
 Narraghmore
 Newcastle
 Powerscourt
 Rathdrum
 Wicklow

Other entities
 East Glendalough School