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Brennan Family History
Ó Braonáin - anglicised Brennan, earlier O Brenane et al. a diminutive of Braon, of uncertain meaning.
Mac Branáin - anglicised Brannan, Brennan, earlier M'Brenan etc. the root probably being a diminutive of 'Bran', probably for 'raven'.Ó Branáin- this name added by Woulfe in 'Sloinnte Gaedheal is Gall' (1923). From 'Bran' or 'raven'.
Of the first name there were several families throughout Ireland: of Ossory in northern Co Kilkenny, where they were chiefs of Uí Duach, and a numerous name there; of Crevagh in Co Westmeath, also numerous there; a family in the south east of Co Galway, influential and numerous at the end of the 16th century; Uí Bhraonáin of Dunkerron in Co Kerry.
Of the second surname we look to Co Roscommon to find the Mac Branáin family that anciently held considerable power in Corca Achlann. Legend has it that they were of druidic descent, but were friendly to the evangelising St Patrick! This name, like the two others, has long been generally anglicised as Brennan.
Woulfe (op. cit.) writes that Uí Bhranáin were ecclesiastics in Derry and Co Fermanagh. There may have been some confusion with the distinct surname Brannagan (Ó Branagáin).
From these disparate sources we would expect the surname Brennan to be widespread over Ireland.
Looking in the 1659 'Census' of William Petty, Cromwellian bureaucrat, we find under the appelation of 'Principal Irish Name' in that document:
(Ó Braonáin)
Co Kilkenny
46 families of Brenan in the barony of Gowran; barony of Ida etc.; Knocktopher, Brenan 06; Skillelogher, Brenon 09; Crannagh Brenon 08.
Co Westmeath
Corkerie barony, Branan & Brenan 05; Fertullagh, Brynan 05, Brenan 02; Moycashel, Brenan 05, Brynan 05.
Co Kerry
Barony of Trughanac, O Brenane 11; there are none listed in the Dunkerran Barony in the 'Census'.
Co Laois
Ossory Barony, Brenan 06; Upper Ossory, Brenan 10; Cullenagh, Brenan 10; Maryborough, Brenan 10; Sliemargagh, Brenan 28; Ballyadams, Brenan 7; Stradbally, Brenan 9.
I could find no trace of Ó Braonáin in the lists for Derry or Fermanagh.
Co Monaghan
O Brynan, 09.
(Mac Branáin)
Co Roscommon
Barony ibid. and Athlone borough, Brenan 7 Branan 07; Boyle Barony, O Brenan & Brennan 30; Athlone Barony, Brenan 9.
By the time of the mid 19th century Griffith's 'Valuation' of households, the most numerous Brennan households were in the following counties: Kilkenny 648, Laois 365, Sligo 271, Roscommon 255, Mayo 233 and Wexford 148.
The 1890 births distribution of Brennan is: Leinster 178, Connacht 94, Munster 50 and Ulster 36.
The arms opposite are self explanatory as to which family they apply. The Irish Times Ancestor website chooses and illustrates the following arms for Brennan: 'Gules, two lions rampant, combatant, supporting a garb all or, in chief three swords, two in saltire points upwards, and one in fess point to the dexter, pommels and hilts of the second: Crest: an arm in armour, grasping a sword, all proper'.
Two famous Brennans
John Brennan (1625-1693) Archbishop of Cashel in this tubulent period.
Abbé Pierre O Brenan, executed by revolutionaries in France in 1794.
