An uncle or near relation was Amlaíb Ua Donnubáin, last known king of Uí Chairpre Áebda (Cairbre Eva), slain in 1201.
The compilation of primarily Munster annals known as Mac Carthaigh's Book, collected by the celebrated Prince and historian Florence MacCarthy, reports the events several years after Crom's death as follows: MCB1259.1: A.D. 1259.
Fínghin Reanna Róin son of Domhnall God Cairbreach [Mac Carthaigh] and the Uí Dhonnabháin killed Mac Craith son of Diarmaid son of Donnchadh na hImirce Timchill [Ó Mathghamhna] in retribution for the slaying of An Crom [Ó Donnabháin] at Inis Béil Átha Dos by the Uí Eachach, about a cowherds' brawl.This Fínghin Reanna Róin is none other than Fínghin Mac Carthaigh, King of Desmond, who two years later would be the victor at the Battle of Callann, and whose father Donal Gott MacCarthy, also King of Desmond, was the founder of the MacCarthy Reagh dynasty, Princes of Carbery.
However, in this case the source is probably Cromad, name for the bend in the River Maigue becoming the modern Croom, County Limerick.
Finally the Sliocht Taidhg Mhic Niocaill and Clann Chonghalaigh, both also found within O'Donovan territory, possibly represent unrecorded generations.