The five most traditional and common Irish surnames are Murphy, Kelly, O'Sullivan, Walsh and Smith, according to an 1891 survey known as the Matheson Report. The next most popular names are O'Brian, Byrne, Ryan, O'Connor and O'Neill.
Due to the history of colonization and onetime English hegemony in Ireland, traditional Irish surnames have undergone considerable change. Consequently, many names that possessed an original Gaelic spelling and pronunciation subsequently accrued anglicized equivalents or translations. For instance, in the original Gaelic, Murphy was ó Murchadha, and O'Sullivan was ó Súilleabháin. It was also the original Gaelic that carried the names' meanings: ó Murchadha meaning "sea-battler;" and ó Súilleabháin means "dark-eyed."
Many other common Irish surnames reveal these patterns. O'Connell, for example, is derived from ó Conaill, meaning "strong as a wolf." Kennedy comes from ó Cinnéide, an adjective meaning "helmet-headed." Another frequently encounter name, Murray, is the anglicized version of the Gaelic ó Muireadhaigh, meaning "lord" or "master." Daly comes from ó Dálaigh, which suggests those that "meet frequently," such as a council might. Other common surnames that are ranked in the top 50 of the Matheson Report include Wilson, Dunne, Burke, Clarke and Martin. Also common are Martin, McGuire, Nolan, Flynn and Fitzgerald. Finishing the top 50 are surnames O'Mahoney, Boyle, Healy, O'Shea and White.