Kavanagh (surname) Kavanagh (surname) Kavanagh or Kavanaugh is a surname of Irish origin, Caomhánach in Irish Gaelic. It is properly "Mac Murchadha Caomhánach" (an example of an Irish agnomen; see "Ó Catharnaigh Sionnach" or Fox of Fir Teathbha), but is often now rendered 'Caomhánach' or rarely 'Ó Caomhánaigh'. "Kavanagh" and "Kavanaugh" are anglicised variations of the Irish Gaelic surname Caomhánach (Cʌoṁʌ̃nʌċ in traditional Gaelic script). The surname was first assumed by Domhnall Caomhánach (the eldest son of the 12th century King of Leinster, Diarmait Mac Murchada) in Ireland. A considerable number of anglicised variations of Caomhánach exist, with some of the most
Eolais mac Biobhsach manuscripts going back almost two hundred years. O'Donovan claimed the family name ( "descendent of Eolais") is still found anglicised as "Olus" or "Olis". two instances of the surname corrupted as "Oelase" and "Olase", are found in the Irish Fiants for Leinster. The surname must be very rare. Eolais mac Biobhsach Eolais "mac Biobhsach" (alias " "knowledge", anglicized "Wallis", "Olis" or "Olus" ) was a chieftain of 10th century Gaelic Ireland. He is noted as the first "full chieftain of Conmaicne Réin". His descendants, "the Muintir Eolais", expanded into the territory of present day south county Leitrim, and parts of