An Crom Ua Donnubáin or Crom O'Donovan is the individual characterized as the ancestor of O'Donovans later found in Carbery in County Cork, and later still in distant County Wexford in Leinster. Nothing is known for sure of his life but his progeny, and the circumstances of his slaying and further events which followed. He was the son of Máel Ruanaid,, son of Aneislis, son of Murchad, son of Amlaíb, son of Cathal, son of Donnubán,, son of Cathal. An uncle or near relation was Amlaíb Ua Donnubáin, last known king ofUí Chairpre Áebda, slain in 1201.
An Crom translates directly from the Irish into The Bent, recalling memories of the infamous deity Crom Cruach. However, in this case the source is probably Cromad, name for the bend in the River Maigue becoming the modernCroom, County Limerick. Crom is claimed in the O'Donovan pedigrees to have been seated here and built a great fortress, although this was more likely built by his ancestor/relation Diarmaid O'Donovan. It is the origin also of the war cry "Crom Abu" of the Kildare branch of the FitzGerald dynasty, who are said to have taken the fortress from Crom.
Issue
His wife or wives are unknown. The following list, down to the Elizabethan period, sets forth Ancrom's descendants. Through the seventh generation from him, the descendants are as listed by Peregrine Clery and Duald MacFirbis, writing in 1632 and 1650, respectively. Generations 8 through 11 are as set forth by John O'Donovan, in his Appendix to the Annals of the Four Masters. The listing is at odds with other published pedigrees of Clan Cathail, which may be examined by referring to Richard F. Cronnelly's Irish Family History, and which drew upon the genealogy approved by General Richard O'Donovan, a direct descendant of Donal of the Hides. Cronnelly disputed the synthesized pedigree compiled in the Appendix of Annals of the Four Masters, noting that Donal of the Hides' pedigree was very incorrectly given from the Book of MacFirbis by John O'Donovan.
* Donnchad of Loch Crott, ancestor of Clann Lochlainn or Clan Loughlin/Clanloughlin
** Cathal
*** Diarmaid
**** Donnchadh, after whom the pedigree of the Lords of Clanloughlin becomes confused for three or four generations
*****
******
*******
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********* Domhnall na Cartan Ó Donnabháin, Lord of Clanloughlin
********** Domhnall Og na Cartan Ó Donnabháin, Lord of Clanloughlin, died 1629
Of the remaining published septs the Sliocht Raghnaill and Sliocht Diarmada Rua are impossible to place exactly above because of the multiple occurrences of the names, while the later sept of O'Donovan's Cove are believed to descend from a near kinsman of Donal of the Hides. Finally the Sliocht Taidhg Mhic Niocaill and Clann Chonghalaigh, both also found within O'Donovan territory, possibly represent unrecorded generations.