While at Clonard, Aedan made friends with Molaise, who would later found the monastery of Devenish Island on the River Erne.

[2] Along with Saint Cadoc, he was said to have exterminated an army of Saxons or Irishmen by rolling stones upon their camp in a narrow valley.

He returned to Ireland in 570, landing on the coast of Wexford with hives of honey bees, which he had been told were scarce on the island.

[7] Aidan seems to have played a role in the king of Leinster's defeat over the Uí Néill High King Áed mac Ainmuirech of the Cenél Conaill at the Battle of Dún Bolg in 598, either (according to the hagiographers) through the intercession of his prayers[2] or (according to the poets of the Bóroma Laigen) through a failed peace embassy followed by the successful idea to sneak Leinster's soldiers into the enemy camp inside food baskets.

[9] The grateful King Brandubh then granted him Ferns in County Wexford,[5] where he established a monastery.

He was noted for his benevolence and hospitality:[6] on one occasion, seeing them exhausted by their journey, he permitted beef to be given to a visiting delegation of British bishops during Lent and permitted them to excuse themselves with the claim that the slaughtered cow was merely "milk and vegetables in condensed form" whereas the whey and biscuits the other monks consumed had so many weevils as to occasion "conscientious scruples".

[3] He was said to have broken a jug while fetching ale for his fellow monks; making the sign of the cross over the shards, however, it was repaired and he continued on his errand.

[4] A yoke given to him by David's steward purposefully too small to fit the necks of his oxen miraculously accommodated them and permitted him to bring the necessary materials for Llanddewi Velfrey.

[2] Miraculous blessings from Aidan were credited with King Brandubh's victory at Dún Bolg in 598; with the selection of his successor Dachua (Mochua Luachra); and with the success of the Irish architect Gobán Saor.

The Catholic episcopal seat formerly located at Ferns (prior to its destruction) is now at St. Aidan's Cathedral in Enniscorthy, although the bishop resides at Wexford.

Saint Áedan's is located on the site (and partially includes the ruins) of the earlier Catholic cathedral, which was burnt down in 1575 by the O'Byrnes of Wicklow.

The clay or mortar from the ruins of the church is said to provide protection against fire or drowning and is kept by many local people in their homes.

[1] The church of Llawhaden, also in Pembrokeshire, Wales, commemorates him near the site of a ford he supposedly discovered while leading his oxen.