Origin of the Casey Clan Name


In ancient times, O’Casey came from the gaelic, O’Cathasaigh word meaning watchful or Vigilant in War.The O’Caseys were descendants of the O’Carrolls,the Princes of Ely. The Princes of Ely were in turn descended from the Kings of Munster. The Ó Cathasaigh ascended into at least five distinct septs. Most of them originated in County Cork and County Limerick although they are also found in the counties of Cork, Dublin, Fermanagh, Mayo and Louth / Monaghan areas. In medieval times the most prominent Caseys came from the Dublin and Fermanagh areas. The name is still numerous in all of these Counties today.

O'Casey Clan Crest

The coat of arms shown are those of the County Limerick sept  from Liscannon, who were part of the great Dál gCais tribe, in turn descended from Cas who were a prehistoric figure of Celtic mythology.

The three eagles on the crest many descend back to one of the old tribal gods of the Dal gCais, the eagle had a legendary ability to look at the sun without blinking. The red colour of the arms suggests warriors and military strength. The roof-like chevron represents protection and faithful service.

An early recorded Casey in this area was John Keegan Casey a Poet and a Fenian, 1846 – 1870.

Variaions include Casey, O’Casey, MacCasey among many more.