Synod of Kells
The Synod of Kells took place in AD 1152, under the presidency of Cardinal Paparoni, and continued the process begun at the Synod of Rathbreasail of reforming the Irish church. The sessions were divided between the abbeys of Kells and Mellifont, and in later times the synod has been called the Synod of Kells-Mellifont and the Synod of Mellifont-Kells.
Máel Máedóc Ua Morgair (Saint Malachy) was made a priest in 1119, as vicar to Celsus. His first sees were Down and Connor, and he was located at Bangor Abbey. On the death of Celsus in 1129, Malachy was nominated as his successor at Armagh, now the prime see in Ireland. An internal church dispute over the succession and proposals for reform obliged him to concede the position to Gelasius. In 1137, Gelasius, lacking papal confirmation of the appointment of Malachy by Rome asked him to secure the archbishop’s pallium at the hands of the Pope or his legate. Malachy reached Rome but the Pope, Innocent II, would only grant the pallia to Malachy at the request of an Irish National Synod. To facilitate this, he made Malachy his papal legate. Malachy then returned to Ireland accompanied by a number of Cistercian monks provided by St. Bernard.
The synod of Kells 
In 1148 a synod of bishops was assembled at Inispatric. Malachy set out on a second journey to Rome, but died on the way at Clairvaux, France, in November. A synod was summoned to Kells in 1152. This synod approved the consecration of four archbishops. Tairrdelbach Ua Conchobair, the High King of Ireland, approved the decrees, and the pallia were conferred by the Papal Legate Cardinal Giovanni Paparoni.
Ireland was divided into thirty-six sees, and four metropolitan sees: Armagh, Cashel, Tuam, and Dublin. Armagh was granted Primacy (see Primacy of Ireland). The diocese of Dublin, ruled by the Ostmen (Hiberno-Norse), seceded from Canterbury and was united with Glendalough. Gregory, the incumbent bishop, accepted the new title and Ostman separatism came to an end.
The diocesan system 
The diocesan system was further reorganised, with the number of metropolitan provinces being increased from two to four, by raising the dioceses of Dublin and Tuam to archdioceses. The four provinces of Armagh, Cashel, Dublin and Tuam corresponded to the contemporary boundaries of the provinces of Ulster, Munster, Leinster and Connacht respectively.
The diocesan structure established by the synod largely survived until the sixteenth century, and still forms the basis of the territorial structure of both the Roman Catholic church and the reformed Anglican Protestant Church of Ireland, with many of the sees now merged.
Provinces and dioceses 
Province of Armagh 
- Ardagh: reduced in size by creation of Diocese of Kells
- Clonard: confirmed as see for East Meath
- Dar-Luis: status of area uncertain
- Kells: established as see for the Kingdom of Breifne. Absorbed by Diocese of Meath in 1211
- Louth: see moved from Clogher and area extended at the expense of Armagh. See returned to Clogher by 1192
- Maghera: see transferred to Derry in 1254
- Raphoe: created in the late 12th century subsequent to the synod
Province of Cashel 
- Ardfert: lost territory to Scattery Island
- Cloyne: formed from part of Cork
- Cork: lost territory to Cloyne and Ross
- Kilfenora: formed from part of Diocese of Killaloe; corresponded with the sub-kingdom of Corco Mruiad
- Killaloe: lost territory to new dioceses of Kilfenora, Roscrea and Scattery Island
- Limerick: lost territory to Scattery Island
- Lismore: formed from part of Waterford
- Roscrea: formed from part of Killaloe, only existed until the 1160s
- Ross: formed from part of Cork
- Scattery Island: formed from parts of Ardfert, Killaloe and Limerick. Incorporated into Limerick by end of 12th century
- Waterford: lost territory to create Lismore
Province of Dublin 
Province of Tuam 
- Mayo: merged with Tuam 1202
- Roscommon moved to Elphin 1156
- Annaghdown was created circa 1179
See also 
- Peter Galloway, The Cathedrals of Ireland, Belfast 1992
- Geoffrey Keating. Foras Feasa Book I-II Geoffrey Keating. http://www.ucc.ie/celt/published/G100054/text090.html The History of Ireland http://www.ucc.ie/celt/published/T100054/text091.html