What's that all about? My grandfather watched Atlanta burn, his great grandfather was born in Virginia the same year as Thomas Jefferson, and that ancestor's grandfather was married in Maryland in 1703. I am about as southern as they come and I have always felt welcome here. I must have missed the memo.
Understanding Your Irish Surname
by Pat Friend
Irish surnames as they exist today have evolved over the course of the centuries with influence applied by both politics and the church. A surname today may be an outgrowth of the Gaelic clan system, courtesy of the Norman invasion, or a mix of several factors.
In ancient Ireland, as in the rest of Europe, individuals were known only by one name. Surnames began to come into use around the tenth century when populations grew and became more mobile. The Gaelic Clan provided a logical patronymic convention for the Irish. "O" or "Ua" or "Ui" meaning "grandson of" meant early surnames such as O'Cleirigh (O'Cleary), meaning "grandson of the clerk". Brian Boru, the High-King of the Irish, didn't use a surname. His grandson, however, became known as Teigue Ua Briain and eventually this became O'Brien.
The next step in the convention was the use of "Mac", which means "son of", and is abbreviated "Mc". As in the example of O'Cleary, above, many of the surnames evolved from the occupation of the father or grandfather. A smith for example, was a gabhann, so his son and eventually his family became Mac Gabhainn, or McGowan. Descendants of carpenter's son known as Mhac an t'Saoir would eventually become McAteer, or MacAtee.
The church had a contribution to make in the development of surnames as well. "Giolla" meant "follower" and led to someone Gilmartin (or Kilmartin), which was originally Mac Giolla Mhartain, "son of a follower of St. Martin." Mul as a prefix evolved from "maol" (meaning "bald"), leading to Mulrennan from O'Maoilbhreanainn, "grandson of a follower of St. Brendan". (St. Brendan was a monk and therefore would have been "bald" because of his tonsure.)
The Norman invasion brought with it a set of new surnames (Power, Roche, and Walsh among others) as well as a variation on the patronymic. "Fitz", in modern times considered distinctively Irish, grew out of the French "fils", meaning "son". So, Fitz and Mac mean basically the same thing, as do Fitzgerald and Mac Gearailt.
The arrival of Cromwell and the Plantation of Ulster brought Scottish names, which remain common in Ulster today. The ongoing English presence, however, had a more lasting effect on the native Gaelic and Norman names. During the time when the Penal Laws were if force it became unpopular, if not dangerous, to have a Gaelic (i.e. Catholic) name. "O", "Mac" and "Mc" were dropped. Names were translated into the English. The McGowan mentioned above, for example, might have become the English "Smith".
Finally, the late 19th century gave birth to a Gaelic Revival and the spread of a spirit of nationalism brought a return of some of the earlier conventions. "O", "Mac" and "Mc" were back in many cases. Grady, became "O'Grady" again.
http://allaboutirish.com/library/gen/undersurname.shtm
This was the custom or pattern of most European families
While today's parents may feel free to chose children's names without regard for an unwritten rule, the Irish traditions of selecting children's names may actually prove a good tool for anyone trying to research Irish family history. Children within a family were traditionally named according to the following pattern:
First son after father's father
Second son after mother's father
Third son after father
Fourth son after father's oldest brother
Fifth son after mother's oldest brother
First daughter after mother's mother (or father's mother)
Second daughter after father's mother (or mother's mother)
Third daughter after mother
Fourth daughter after mother's oldest sister
Fifth daughter after father's oldest sister
It's important to consider names in all their forms when looking at family use of the traditional naming patterns. A few examples are: