Irish Family Names 

By Peadar O'Donovan, Skibbereen Printers 1991

The O'Donovan name, according to Peadar O'Donovan, has been associated with SouthWest Cork for 800 years. O'Donovans and their kinsmen, the Collinses and the Connollys, were forced south around 1200 A.D. by the Geraldines, after the Norman invasion (1169), from the kingdoms of Ui Conaill Gabhra and Uí Cairbre Aofa in Co. Limerick.

He suggests that the warcry "Crom Abú" was the O'Donovan warcry, first heard in Croom, Co. Limerick where Crom, the progenitor and chieftain of the O'Donovan Clan built a castle 200 years before the Norman invasion. This warcry was later to be taken up by the Fitzgeralds.

He goes on to explain the derivation of the name. Derived from Donndubháin, Donn being a proper name of those of noble rank and dubháin signifying anything black, especially a black haired person. Surnames came into usage around 1000 A.D. the name became Ó Donnabháin, meaning grandson (Ó) of Donovan.

The O'Donovans were originally located at Bruree, in the valley of the river Maigue, in what is now Co. Limerick. The "O'Donovan" tuath was called Ui Fidhgeinte, (Ee Fee-yinte) -- and approximated to the present diocesse of Limerick. About 950, Ui Fidhgeinte split into two separate "tuatha" -- the eastern one taking the name Ui Cairbre (Ee Cairb-reh). The old royal family became kings of this new "tuath" with Bruree still as their headquarters. For this reason they were sometimes described as the kings of Bruree.
Despite the fact that Cathal O'Donovan marched to Clontarf with Brian Boru, the memory of old feuds and distrust continued between the O'Donovans and the O'Briens (descendants of Brian Boru). A climax came in 1178, when Donal Mor OBrien, King of Thomand (North Munster) expelled the O'Donovans from their Co. Limerick base. They were eventually settled in the West Cork by the Mac Carthys, bringing with them the name of their ancestral territory, Ui Cairbre, a name that still survives in the west Cork barony names, Carbery East and Carbery West.
In Bruree one may still see the ring forts, those ancient earthen enclosures with their surrounding banks and fosses -- now largely overgrown with trees and bushes -- within which, in far distant days, stood the wood - constructed residences of the kings of Ui Fidhgeinte and Ui Cairbre, the forbears of the O'Donovans of Bruree and West Cork.