The Clan/Sept History

McCarthy (a variant of MacCarthy), meaning "Son of love", is a common surname that originated in Ireland and is in fact the most common of all the names which uses the prefix Mac or Mc, meaning son of. There are several forms extant, including Carthy and Carty. 60% of people with the surname in Ireland still live in County Cork where the family was very powerful during the medieval period. The origin of the name begins with Carthach an Eóganacht Chaisil king who died in 1045 in a house fire deliberately started by one of the Lonergans. Carthach was a contemporary and bitter rival of the semi-legendary Brian Boru and the McCarthy clan were pushed out of their traditional homelands in the Golden Vale of Tipperary by the expansion of that sept in the middle of the twelfth century. His son used the appellation Muireadhach mac Carthaigh (Muireadhach, son of Carthach), a common practice. Muireadhach (anglicized as "Murray") died in 1092. His sons, Tadhg and Cormac adopted MacCarthy as a proper surname. Following the treaty of Glanmire in 1118, dividing the kingdom of Munster into Desmond and Thomond, this Tadhg became the first king of Desmond, comprising parts of the modern counties of Cork and Kerry. For almost five centuries they dominated much of Munster, with four distinct branches: those led by the MacCarthy Mór (Great MacCarthy), nominal head of all the MacCarthys, who ruled over much of south Kerry, the Duhallow MacCarthys, who controlled northwest Cork; MacCarthy Riabhach or Reagh ('grey') based in Carbery in southwest Cork; and MacCarthy Muskerry, on the Cork / Kerry border. Each of these families continued resistance to Norman and English encroachment up to the seventeenth century when, like virtually all the Gaelic aristocracy, they lost almost everything.

The number of references to the MacCarthys in the Annals, especially the "Annals of Innisfallen", is very great. Cárthach was the son of Saorbreathach, a Gaelic name which is anglicised as Justin, and in the latter form has been in continuous use among various branches of MacCarthys for centuries. Another Christian name similarly associated with them is Finghin, anglice Fineen, but for some centuries past, for some obscure reason, Florence (colloquially Flurry) has been used as the English form. From the thirteenth century, when Fineen MacCarthy decisively defeated the Geraldines in 1261, down to the present day, Fineen or Florence MacCarthys and Justin MacCarthys have been very prominent among the many distinguished men of the name in Irish military, political and cultural history. Until the dissolution of the kingdom in 1596, the crown was vested in the hereditary possession of the Mac Carthy (by the law of tanistry).