Changes in Ecclesiastical Jurisdictions in Northern Ireland

Date	Change
445	Archdiocese of Armagh was established
450	Abbacy nullius of Down was established
454	Abbacy nullius of Clogher was established
500	Abbacy nullius of Brefinnia was established
514	Abbacy nullius of Dromore was established
550	Abbacy nullius of Derry was established
570	Abbacy nullius of Ardstraw was established
1111	Abbacy nullius of Clogher was promoted as Diocese of Clogher
1111	Abbacy nullius of Ardstraw was promoted as Diocese of Ardstraw
1152	Abbacy nullius of Brefinnia was promoted as Diocese of Brefinnia (became suffragan of Armagh)
1152	Diocese of Ardstraw was suppressed (to Diocese of Cinél nEógain and Ardstraw)
1152	Archdiocese of Armagh was promoted as Metropolitan Archdiocese of Armagh (with suffragan sees Ardagh, Brefinnia, Ceanannus Mór, Cinél nEógain and Ardstraw, Clogher, Clonard, Connor, Down, Duleek, Raphoe and Louth)
1152	Abbacy nullius of Derry was promoted as Diocese of Cinél nEógain and Ardstraw (gained territory from the suppressed Diocese of Ardstraw and became suffragan of Armagh)
1152	Abbacy nullius of Down was promoted as Diocese of Down (became suffragan of Armagh)
1173.02.11	Diocese of Cinél nEógain and Ardstraw was renamed as Diocese of Maghera, Cenél Fearadhaigh and Ardstraw
1180	Abbacy nullius of Dromore was promoted as Diocese of Dromore (became suffragan of Armagh)
1254	Diocese of Maghera, Cenél Fearadhaigh and Ardstraw was renamed as Diocese of Derry
1442	Diocese of Down was renamed as Diocese of Down and Connor
1460	Diocese of Brefinnia was renamed as Diocese of Kilmore
1969	Titular Episcopal See of Árd Sratha was restored