Top 10 facts you never knew about Irish surnames

Being one of the first countries in the world to ever use surnames, family names play a huge role in Irish history. Here are our top ten facts you never knew about Irish surnames.

Our surnames can tell us a lot about who we are: where we’re from, who our descendants are, and what kind of jobs they did. Have you ever wondered what the common Irish prefixes Mc and O’ mean? Or what is the difference between Mac and Mc? If so, you’ve come to the right place.

Keep reading to find out our top ten facts you never knew about Irish surnames.

Ireland Before You Die’s overview of facts you never knew about Irish surnames

  • Ireland has a long and varied history, with different forms of foreign and external influence. One of those influences is Norman, who brought with them the prefix “Fitz”.
  • The famous American actress Marilyn Monroe previously had an Irish surname. She was born as Norma Jean Baker, and chose Marilyn Dougherty as her stage name.
  • Ireland is believed to be the first place in all of Europe that had surnames, leaving Irish surnames the oldest across the continent.
  • The name ‘Murphy’ actually used to be ‘O’Murphy’. The name is now so popular that more Murphy’s live in England and the USA than in Ireland.
  • When English rule strengthened in Ireland in the 17th century, some people were forced to drop the prefixes of ‘O’ and ‘Mac’ in their surname.

10. Irish surnames were the first in Europe

Ireland was one of the first countries in Europe is have surnames, thats why Irish surnames are so old.

Ireland is believed to be the first country in Europe to start using surnames. The oldest surviving evidence of a surname dates back to 916 AD when the death of Tigherneach Ua Cleirigh, Lord of Aidhne in Galway was recorded. Thus, O’Cleirigh is not just the oldest surviving surname in Ireland, but the whole of Europe.

9. Elizabeth I once banned the name O’Neill

Queen Elizabeth I once banned the name O'Neill due to a falling out.

Sean, or Shane, O’Neill, earl of Tyrone in the mid-1500s, caused a lot of trouble for the English dynasty and thus, Queen Elizabeth banned the name O’Neill. Those who used the name would either be sentenced to death or forced to forfeit their property. Today O’Neill is in the top ten Irish last names, and Sean is a top ten name given to boys in Ireland.

8. No difference between Mac and Mc

There's no difference between Mac and Mc, one is mainly Scottish while the other is Irish.

The prefixes Mac and Mc used to be used interchangeably, and it was only in the late 1800s that people began to care about the spelling. The contraction appears more in Irish surnames than in Scottish, as two out of three Mc surnames originate in Ireland. In comparison, two out of three Mac surnames originate in Scotland.

7. Irish surnames with O or Mac used to lead to prejudice

Those with Irish surnames used to be treated with prejudice.

In the 17th century, English rule strengthened over Ireland and with that many people dropped the prefixes O and Mac in their surnames because it became challenging to find work if you had an Irish sounding name.

Many of these prefixes were readopted by families in the 1800s. However, the wrong prefix was occasionally adopted, for example, adding an O when the original prefix was Mac.

6. Murphy used to be O’Murphy

The Irish surnames Murphy used to be O'Muphy back in the day.

For some names, the prefixes were never readopted. One example is the popular surname Murphy which was originally Ó Murchadha, or O’Murphy. Today more Murphys live in England and America than in Ireland.

5. Marilyn Monroe

Marilyn Monroe was going to choose one of our Irish surnames before she landed on using Monroe as her stage name.

Did you know that Marilyn Monroe originally had an Irish surname? The actress was born Norma Jean Baker and chose Marilyn Dougherty as her stage name. She was forced to drop it as 20th Century Fox felt it was too difficult for American fans to pronounce.

Today many Hollywood stars choose to keep their original Irish names, including people such as Saoirse Ronan and Ciarán Hinds.

4. One tombstone with six different spellings

Irish surnames were spelt differently throughout history meaning there's no one way of spelling them.

In the past, the spelling of surnames wasn’t as fixed as it is today. For example, there is a tombstone in Ireland where the name for a family is spelt differently for each member. The tombstone reads McEneaney, McAneany, McAneny, McEnaney, McEneany – and Bird, from the belief that the name came from éan which meant bird.

3. Norman influence affected Irish surnames

Under Norman influence, Irish surnames took on a bunch of Norman additions, like Fitz.

One hundred years after the Norman conquest of England in 1066, they turned their attention to Ireland. Many Norman lords then became independent of London and began adopting Irish customs, including Irish language and Irish names.

During this invasion, the Normans brought with them the prefix ‘Fitz’, which is derived from Latin and means “son of”.

2. O and Mac names weren’t always family names

The Irish surnames that began O and Mac weren't always family names.

Surnames with the prefixes Mac and O, meaning “son of”, have their first recorded usage in the 12th century. However, these names did not always denote familial relations.

Instead, when land passed to the control of a new clan due to warfare, the local population would adopt the name of the new chief to help them keep their rule. Surnames for common folk did not come into regular use until the 1500s.

1. Son of/Daughter of

Many Irish surnames come from the child's father with the form dependent on the child's gender.

Many Irish surnames come from the child’s father, and the form of the name is dependent on whether the child is male or female.

A male’s surname generally takes the form Ó/Ua which means “descendant”, or Mac meaning “son of”, followed by the genitive case of a name, as in Ó Neill for “descendant of Neill” or Mac Lochlainn for “son of Lochlann”.

A female’s surname replaces Ó with Ní meaning “daughter of descendant of”, and Mac with Nic for “daughter of the son of”.

Your questions answered about facts you never knew about Irish surnames

Below, we have put together some of the most frequently asked questions from our reads and online about the facts you never knew about Irish surnames.

What is the most unusual Irish surname?

An usual Irish surname would be Ó Gogáin (Goggin). It finds its origins in the Irish word of “gog”, which means “a small, misshapen or twisted object”.

What is the oldest Irish last name?

The oldest Irish last name is Ó Cléirigh (O’Cleary/O’Clery). Dating back to 916 AD, this is regarded as the oldest surviving surname in Europe.

What are the rarest Irish surnames in Ireland?

These would include Hickey, Tobin, Hawkins, Pattison and Cussen.

What is a very Irish last name?

Some very Irish last names would include Murphy, Byrne and O’Brien. They are widely regarded and known as Irish names.

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