Possible Origins of the surname Fagan
According to Edward MacLysaght1, "Fagan - usually of Norman origin in Dublin and Meath. Sometimes Ó Faodhagáin [Ó Faogáin] in Co. Louth which, however, is there usually anglicized Fegan. Dr. John Ryan and other scholars regard this as an Oriel sept distinct from O'Hagan, with which Woulfe equates it."
We have possible origins as Normans, O'Hagans or as Ó Faogáins. It can be surmised from the various possible histories of the name, we may have been King-makers, owners of castles, mayors of Dublin, and clergy. We that share the name, or its variants may trace our actual lineage back to different sources!
Loosely, we represent a common surname association, an association of 'tribes' all sharing the same name or variants. Irish clans are traditional kinship groups sharing a common surname and heritage and existing in a lineage based society prior to the 17th century. Often, clans are thought of as based on blood kinship alone; in fact Irish clans would be better thought of as akin to the modern-day corporation.2 In that sense, we are a Clan, but in a more succinct sense, we are an association of tribes.
The Ó Faogáin theory:
Many 'Last Name' sites indicates that Fagan is an Anglicized version of Ó Faodhagáin from E. Airgialla (the ancient territory of Oriel). According to the now defunct Irish information website called GoIreland.com3, "it is true, a Gaelic Irish family of Ó Faodhagáin, anglicized Fagan, which belongs to Co. Louth. ...[some scholars concur with] a statement made by Fr. Woulfe that Ó Faodhagáin is a variant of Ó hAodhagan (O'Hagan) and other scholars disagree. They say it is a distinct sept of eastern Airghialla (Oriel). There Fagan, Fegan, Feighan and Feehan are numerous and much confused; probably these all derive from Ó Faodhagáin."
The Norman Origin theory:
Many 'Last Name' sites as well as O'Laughlin4 indicate that the name may be of Norman origin. There are several sources that point to Fagans as being in the first wave of Norman settlers. The Norman Fagans, according to sources, were mainly in Dublin & Meath. Much of the information I have been able to find on the Fagans is from the Dublin area.
Again, from GoIreland.com5, "In spite of its very Irish appearance (gan is one of the most common terminations of Irish surnames) Fagan must be regarded as a family name of Norman origin. At the same time it must be pointed out that it is not an English name. It is derived from the Latin word paganus. For many centuries it has been associated with Counties Dublin and Meath. As early as the year 1200 one William Fagan was the owner of extensive house property in the city of Dublin and fifty years later we find the family firmly established in the neighbouring counties with a seat, acquired a little later, at Feltrim, Co. Dublin. A branch of this family was also found in Kerry and another in Cork city where Christopher Fagan took refuge in 1497 - he had been a supporter of Perkin Warbeck's claim to the throne and Cork was solidly behind that pretender. From the Kerry branch were descended the Fagans who distinguished themselves in the service of France in the eighteenth century and were ennobled in that country. The name is not really numerous in Ireland - it is estimated that about two thousand of the population are so called (almost all these are natives of Leinster, fifty per cent of whom are Dubliners)."
The Ó Fiacháin theory:
1 MacLysaght, Edward. The Surnames of Ireland. Blackrock, Co. Dublin: Irish Academic, 1985. Print.
2 Nicholls, K. W. Gaelic and Gaelicized Ireland in the Middle Ages. Dublin: Lilliput, 2003. Print.
3 GoIreland.com was operated by Gulliver Ireland, which is headquartered in Killorglin, County Kerry and was "Ireland’s leading cost effective provider of tourist information and reservations." The URL for the information regarding the Fagan name was here, but can now be found archived here.
4 O'Laughlin, Michael C. The Irish Book of Arms: Genealogy and Heraldry from the Earliest times to the 20th Century. Kansas City, MO: Irish Genealogical Foundation, 2000. Print.
5 GoIreland.com, ibid.
6 Email (dated August 5, 2015) from Proinsias Mag Fhionnghaile, the McGinley Clan Historian.
7 "Ó FIACHÁIN." Library Ireland. LIBRARY IRELAND, n.d. Web. 05 Aug. 2015.