Aengus M'Uathamore
Aengus M'Uathamore, a distinguished Firbolg chief of the 1st century, who after the battle of Moytura, where the Firbolgs were defeated by the Tuatha-de-Dananns, took refuge in the Aran Islands with his brother Conor. Meave, Queen of Connaught, granted them the islands. He is generally reputed to have been the builder of Dun Aengus, the great fort on Aranmore, upon the summit of the southern cliffs, 300 feet above the sea. Its sea front measures about 1,150 feet. The walls are some 13 feet thick and 18 feet high. The land approaches are defended by rude chevaux-de-frise of splintered rocks. Sir William Wilde characterized this fort as "the greatest barbaric monument of its kind in Europe." A fort on Inismaan is called Dun Conor, after Aengus' brother Conor; while the name of his brother Mil is associated with the strand of Port Murvey, known in Irish as Muirveagh Mil, or " The sea-plain of Mil."
Sources
9. Aran Isles—Papers by Sir William Wilde, (1857); and by G. H. Kinahan, in Science Gossip, 1876. (Pamphlets.)
180. Ireland, Murray's Hand-Book. London, 1866.