Clonard Abbey was founded by Saint Finnian, first Abbot of Clonard, in the early sixth century. There had been a number monastic bishops at the abbey, but it was not until the Synod of Rathbreasail in 1111 that the diocese of Clonard was established. Its boundaries were set at the Synod of Kells in 1152, which covered roughly the western part of the Kingdom of Meath with the diocesan bishop's seat (cathedra) located at Clonard Abbey.[4] During the twelfth century the bishops of Clonard frequently used the title "bishop of Meath" or "bishop of the men of Meath" meaning the original centre of the Kingdom of Meath in Westmeath. Clonard acquired most of Magh Breagh (what is now the county of Meath) by absorbing the diocese of Duleek later in the twelfth century. After Bishop Simon Rochfort transferred his seat from Clonard to Trim in 1202, the title "bishop of Meath" became the normal style.[4][5] The former seat of the diocese of Breifne or the Uí Briuin at Kells was absorbed into Meath in 1211, but that diocese remained extant among the Uí Briúin Bréifne, becoming the diocese of Kilmore.
^Fryde, E. B.; Greenway, D. E.; Porter, S.; Roy, I. (1986). Handbook of British Chronology (Third ed.). Cambridge: Cambridge University Press. pp. 367–369. ISBN0-521-56350-X.
