Keeling, O'Hagan, MacMahon, O'Flynn…surnames are surely one of the most distinctive attributes of the Irish people. Yet how much do we really know about their origin? Do we have any understanding of how they came about ?
Ireland was in fact one of the earliest countries to introduce a system of hereditary surnames. Many of them were already in use by the year 1000, although the system wasn't adopted in its entirety until about one hundred years later. Despite the legend that Brian Boru was somehow responsible for the widespread implementation of this naming system, the custom actually developed of its own accord as the Irish population grew in size.
Originally, the surname was formed by placing the prefix mac ('son of') before the father's Christian name or Ó ('grandson of') before that of the grandfather. In later years, the words giolla and maol were incorporated into the surname, meaning 'servant', indicating that the person was devoted to a certain saint. We can see examples of these in surnames such as Mac Giolla Mhártain (Gilmartin), meaning 'son of the servant of Martin', Ó Maoilbhréanainn (Mulrennan), meaning 'grandson of the devotee of Saint Brendan' or Mac Giolla Bhríde (MacBride), meaning 'son of the devotee of Saint Bríd'. Later still, the father's profession was referred to in the surname, for example Mac an Bháird (Ward), meaning 'son of the bard', or Ó hÍceadha (Hickey), meaning 'grandson of the doctor'.
Other surnames refer to an individual's physical appearance such as Mac Dubhghaill (MacDowell), 'son of the dark stranger', from dubh (black/dark) and gall (foreigner). Other examples include Ó Ruadháin (Ruane) from rua ('red'), Ó Duibhghiolla (Diffily) from dubh (black) and giolla (boy/servant) and Caomhánach (Kavanagh) from bán ('white').
Bear in mind that there is no truth that the prefix Mac is of exclusively Scottish origin. That said however, Ó is more common in Ireland than Mac, which is very common in Scotland. Neither is there any difference between Mc and Mac, the former is simply an abbreviation of the latter. The use of both Mac and Ó is a relatively recent trend. Many people abandoned the prefixes during the 17th Century, when Catholic and Gaelic Ireland were in decline. The following two hundreds years of English rule ensured that they remained buried. It wasn't until the emergence of the Gaelic League in 1893 and the resurgence of interest in the traditions of the past, that they were resurrected.
Many Irish surnames demonstrate the complex history of Ireland in terms of migrations and invasions. The names Burke, Power, Butler and Roche, show the Norman influence from the end of the 12th Century. Other common Norman names include FitzGerald, FitzGibbon, DeBurca, DePaor and D'Arcy. There are other examples of Norse names which were introduced before the Normans, such as Harold and Trant. English surnames coincided with the Cromwellian Settlement and the Plantation of Ulster in the 17th Century. The arrival of the Huguenots around the same time also left its mark.
The fact that Irish surnames are now so common throughout the world is a result of repeated migrations from Ireland. Perhaps the most famous migration, which resulted in the distribution of distinctly Irish names, was that of the 'Wild Geese'. The Wild Geese were Irish nobles and soldiers who went into exile as a result of the Treaty of Limerick - Luimneach signed by Patrick Sarsfield in 1691. Having left Ireland they were accepted into the armies of many continental countries such as Spain, France, Poland and Russia. As such, in past centuries it was not uncommon for high ranking officers in these armies to carry names such as O'Donnell or McMahon. Other families went on to develop interests in agriculture, and it is now possible to buy high quality wines from the Bordeaux region of France produced by such houses as Chateau Kirwan, Michel Lynch and Chateau de MacCarthy.