Annaghdown Cathedral Ruins, Co. Galway
The first monastery was founded by St Brendan of Clonfert in 6th century. Several 'bishops of Annaghdown', from 1189 to 1485, were systematically elected by its 'Cathedral Chapter' and, despite many counterclaims from Tuam, some were approved by Rome. A 15th century building of Annaghdown Cathedral has an inserted east window of the late 12th century. It is a round-headed window with a richly decorated Romanesque frame.
Ardfert Cathedral Ruins, Co. Kerry
It was built between the 12th and 17th centuries on the site of St Brendan The Navigator's 6th-century monastery. The ruin retains impressive Romanesque west doorway, the 13th-century east window, and a beautiful row of 9 lancet windows in the south wall. Also here are two smaller churches.
Ardmore Cathedral and Round Tower, Co. Waterford
It is believed to be the oldest Christian settlement in Ireland. St. Declan lived in the region at some time in the period 350-450 AD and christianised the area before the coming of St. Patrick. There is a well-preserved 12th-century Round Tower and the ruins of a Cathedral and oratory dating from the 13th and 8th centuries respectively.
Cathedral of the Assumption of the Blessed Virgin Mary, Roman Catholic, Tuam, Co. Galway
The original architect was Dominic Madden, who also designed Ballina Cathedral and Ennis Cathedral. The foundation stone was laid on 30 April 1827. Tuam Cathedral is built of limestone in the style of Decorated Gothic. The three-story west tower is 43m high and surmounted by eight richly pinnacles rising above the parapet, which is enriched with open tracery.