11Westropp, T.J. "A Study of the Fort of Dun Aengusa in Inishmore, Aran Isles, Galway Bay: Its Plan, Growth, and Records." Proceedings of the Royal Irish Academy Section C: Archaeology, Celtic Studies, History, Linguistics, Literature 28 (1910): 34.
In addition to Westropp's work in 1909, the most significant of the other investigators were: Roderick O'Flaherty (1684-6) "Ogygia"; Edward Ledwich (1797). "He gives a delusive view...regards the fort as a mandra or monastic enclosure"; John O'Flaherty (1824); George Petrie (1821 and 1857); John O'Donovan (1839); Samuel Ferguson (1853); John Windele (ante 1854); Lady Ferguson (1867). "The Irish before the Conquest"; and Lord Dunraven (ante 1875). He took photographs before the restoration.