Ardfert Friary was founded by Thomas Fitzmaurice around 1253 for the Franciscans. The Friary has a rectangular church with a south transept and south aisle, there are 5 lancet windows in the east wall with the cloister to the north side of the church. At the west end is a 6 story Tower house.
The preperation for the building of the Cathedral to Saint Brendan was begun by Bishop Donald at Ardfert, and would be continued by his successor Bishop David O'Duibhditribh who incorporated some charecteristic relics of the remains of the previous churches into the new building including its western gable, the fine doorway and ornate arcade that graced the Hiberno / Romanesque church of O'Ronan. It is one of the earliest examples of that style that remains in Ireland today.