The Diocese of Elphin was established following the Synod of Rathbreasail in the year 1118. In that year the see for east Connacht was moved from Roscommon. Elphin was the traditional site of a monastic house established by St Patrick c.450, although there are no remains of that date. Following the Reformation, there were parallel dioceses. The Church of Ireland diocese continued from the 16th until the 19th century but since 1841 has been part of the united Diocese of Kilmore, Elphin and Ardagh.