The original cathedral was in the village of Clogher in County Tyrone, site of a monastery founded in 454 by St. Macartan, who was appointed bishop by St. Patrick in the 5th century.

According to tradition, these were originally given to St. Macartan by St. Patrick, although the manuscript as it exists today dates from the eighth century.

[10][11] In that same year the Sunday Business Post newspaper reported that the Bishop, Joseph Duffy, had admitted both to failing to pass abuse claims to police in 1989, and to being party to victims and families being made to sign oaths of non-disclosure.

John McCabe (20 months imprisonment on abuse charges)[15] and Fr Jeremiah McGrath, described by the Belfast Telegraph as "the very antithesis of what a priest should be.

[19] However, the Report did acknowledge that current procedures for dealing with allegations of abuse in the diocese had improved significantly and it praised Bishop MacDaid's approach to the issue.

In December 2023 Bishop Duffy announced that the diocese would start training 40 laymen and laywomen to preside over funerals given the few number of priests.