Clogher is one of the twenty-four dioceses established at the Synod of Ráth Breasail in 1111 and consists of much of south west Ulster, taking in most of counties Fermanagh and Monaghan and parts of Tyrone, Cavan, Leitrim and Donegal. Frequently in the Irish annals the Bishop of Clogher was styled the Bishop of Oirialla. Between c. 1140 to c. 1190, County Louth was transferred from the see of Armagh to the see of Clogher. During this period the Bishop of Clogher used the style Bishop of Louth. The title Bishop of Clogher was resumed after 1193, when County Louth was restored to the see of Armagh.
^Moody, Martin & Byrne 1984, A New History of Ireland, volume IX, pp. 341–343.
References
Cotton, Henry (1849). The Province of Ulster. Fasti Ecclesiae Hiberniae: The Succession of the Prelates and Members of the Cathedral Bodies of Ireland. Vol. 3. Dublin: Hodges and Smith.
Fryde, E. B.; Greenway, D. E.; Porter, S.; Roy, I., eds. (1986). Handbook of British Chronology (3rd, reprinted 2003 ed.). Cambridge: Cambridge University Press. ISBN 0-521-56350-X.
Moody, T. W.; Martin, F. X.; Byrne, F. J., eds. (1984). Maps, Genealogies, Lists: A Companion to Irish History, Part II. A New History of Ireland. Vol. IX. Oxford: Oxford University Press. ISBN 0-19-821745-5.