This most interesting and ancient surname is derived from two possible origins. Firstly, it may be of Scottish locational origin from any of the places called Cairnie in Aberdeenshire, and the surname is also found here as Carney and Carny. However, it is more likely to be of Old Gaelic origin, as one of the Anglicized forms of either the Gaelic "O'Catharnaight", composed of the Gaelic prefix "O", male descendant of, and a byname "Catharnach", warlike; or "O'Cearnaigh", with the byname "Cearnach", victorious. The former sept were chiefs of Teffia, in County Meath, and even when their influence diminished they retained a considerable territory in Kilcoursey, County Offaly. The name from this source is also Anglicized as Fox (Sionnach) as their first recorded namebearer (see below) was nicknamed "The Fox". The latter sept, a branch of the Ui Fiachrach, were located in County Mayo, and later migrated to Cashel. Kearney, Keherney and O'Caherney also derive from this source. There is also a townland called Ballymacarney in County Meath. In Scotland, Philip Carny appears in Karale in 1332. Other early recordings include the christening of Patrick, son of Peter and Sara Cairney at Old Machar, Aberdeen, on February 9th 1724, and the birth of Catherine Cairney on February 8th 1871, at Athlone, County Westmeath, Ireland. The first recorded spelling of the family name is shown to be that of Tadhg O'Catharnaigh, which was dated 1084, in "Medieval Irish Records", during the reign of Irish High Kings in Opposition. Surnames became necessary when governments introduced personal taxation. In England this was known as Poll Tax. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling.