The most historically important family, however, were the O Catharnaigh, from catharnach, meaning "warlike". These were chiefs of a large territory in the midlands, in the modern counties of Meath and Offaly; one of their number became Baron Kilcoursey, from the placename in Offaly. An early chief of this family, Tadhg O Catharnaigh (d.1084), became known as An Sionnach, the fox, and his descendants adopted the name O Sionnaigh, which was later anglicised as Fox.
The multiple origins of the name can be seen in the number of counties containing placenames which incorporate it , including Cork (Ballykearney), Down (Kearney village) Kilkenny (Kearneysbay), Louth (Kearneystown) and Kildare (Kearneystown).
In evolutionary terms the family would appear to be doing well. Ranked 135th in Ireland in 1890, with 147 births, they now stand at 90th, a rise which is a credit to their fecundity.
.Peadar Kearney (1883-1942).was a Dubliner and a member of the IRB. He wrote the words of "A Soldier?s Song" in 1907 and after independence it became the Irish national anthem.
Richard Kearney (1954 - ) has been professor of philosophy at University College Dublin since 1990. Remarkably precocious and prolific, his work is European rather than Anglo-Saxon in outlook. He has also published poetry and fiction.