St. Aedan of Ferns ('Aedh-og or Mo-Aedh-og) was bishop of Ferns, in Ireland, b. at Inisbrefny, near Templeport, County Cavan, about 550; d. at Ferns, 31 January, 632.

When a youth he was a hostage in the hands of Aedh Ainmire, High King of Ireland. He studied at the great school of Kilmuine, in Wales, under St. David, and returned to Ireland in 580, landing on the coast of Wexford. In thanksgiving for the victory of Dunbolg, County Wicklow, 10 January 598, in which King Aedh was slain, Bran Dubh, King of Leinster, convened a synod at which, having represented the great services rendered to the kingdom of Leinster by St. Aedan, notably the remission of the Boromha tribute, it was agreed that Ferns be made an episcopal see, with Aedan as first bishop. He was also given a nominal supremacy over the other Leinster bishops by the title of Ard-Escop or Chief Bishop. King Bran Dubh was slain in Ferns in 605. St. Aedan, popularly known as Mogue (Mo-Aedh-og = my dear Aedh) founded thirty churches in the County Wexford. The episcopal seat of Ferns is now at Enniscorthy, where there is a beautiful cathedral dedicated to St. Aedan, whose patronal feast is observed 31 January. He is patron saint of Ferns.