King of Thomond
From Irish Pedigrees; or the Origin and Stem of the Irish Nation by John O'Hart
THE following is the Stem  of this family, from Cormac Cas, who was the ancestor of O'Briain of Thomond (anglicised O'Brien, Bernard, Brien, Bryan, and Bryant), and a younger brother of Owen Mór, who is No. 85 on the "Line of Heber;" down to Henry O'Brien, the eighth Earl of Thomond, who d. in 1741.
85. Cormac Cas: second son of Olioll Olum, King of Munster, by his wife Sabh or Sabina, daughter of Conn of the Hundred Battles, and relict of MacNiadh; he was one of the most distinguished champions of his time, and "remarkable for strength of body, dexterity, and courage." He defeated the Lagenians (or Leinster men) in the battle of Iorras Damhsa, Carmen (or Wexford), Liamhan (or Dunlaven), Tara, Teltown, and Samhna Hill; and the Conacians in the famous battle of Cruachan, in the county Roscommon. Cormac d. at Dun-tri-Liag, (or the Fort of the Stone Slabs), now "Duntrileague," in the county Limerick, of wounds received in the battle of Samhna Hill, from the spear of Eochy of the Red Eyebrows, King of Leinster. He was m. to Samer, dau. of Fionn MacCumhal (Fionn MacCoole), and sister of the poet Oisin, by whom he left, with other children:
86. Mogha Corb (or Mogha of the Chariots), who was b. A.D. 167, and attained a very old age. This Prince, who became King of Munster, which he governed for the space of twenty years, fought the memorable battle of Gabhra or Garristown, near Dublin, against the Monarch Cairbre Liffechar, A.D. 284.
87. Fear Corb: his son; b. 198; governed Munster for seven years; fought the battles of Tlachtga and Teltown against the Lagenians, in the latter of which he slew Tinne the son of Triun, a distinguished warrior; and defeated the Conacians in the battles of Ceara, Corann, and Rathcruaghan, with great slaughter.
88. Æneas Tireach: his son; b. 232; was distinguished for his patriotism and courage, particularly in the battle of Cliodhna, near Clonakilty; and was remarkable for the strictness of his laws, as well as for his impartial judgments.
89. Lughaidh Meann: his son; b. 286; dispossessed the Firbolgs of the tract now known as the county Clare (which had in his time formed part of Connaught), and attached it to Munster.
90. Conall Each-luath ("each:" Irish, Lat. "eq-uus," Gr. "ik-kos" a horse; "luath:" Irish, agile, Welsh "lludw," nimble), or Conall of The Swift Steeds: his son; b. 312. Had two sons—1. Cas; 2. Eana Arighthach.
91. Cas: the elder son; a quo the Dal Cais or "Dalcassians;" b. 347. Had twelve sons:—1. Blad, 2. Caisin, 3. Lughaidh, 4. Seana, 5. Aengus Cinathrach, 6. Carthann Fionn, 7. Cainioch, 8. Aengus Cinaithin, 9. Aodh, 10. Nae, 11. Loisgeann, and 12. Dealbheath.
92. Blad ("bladair:" Irish, to coax; Lat. "blater-o," to flatter): the eldest son of Cas; a quo O'Bladair, anglicised Blair, Flattery, and Blood (of Munster); b. 388; left four sons:—1. Carthann Fionn Oge Mór; 2. Carthann Dubh; 3. Eochaidh; 4. Brennan Ban, ancestor of O'Brennan (of Thomond), Glinn, Glynn, Maglin, Magan, Muldowney (now "Downey"), O'Hurley, etc.
93. Carthann Fionn Oge Mór: eldest son of Blad. Had two sons: 1. Eochaidh Ball-dearg; 2. Aengus, who was the progenitor of O'Curry, O'Cormacan, O'Seasnain, etc.
94. Eochaidh Ball-dearg: son of Carthann Fionn Oge Mór. Received Baptism at the hands of St. Patrick, and d. at an advanced age, leaving two sons: 1. Conall, 2. Breacan, a quo "Ibrickan," a barony in the county Clare.
95. Conall: the elder son. Died vita patris, and left issue: 1. Aodh Caomh; 2. Molua Lobhar, or St. Molua the Leper, founder of the church of Killaloe, co. Clare.
96. Aodh Caomh ("caomh:" Irish, gentle; Arab, "kom," noble; Lat. "com-is"): the elder son; a quo O'Caoimh, anglicised Coombe. Was King of Cashel. Of him Lodge says: "He was the first Christian King of this family, that became King of all Munster; and his investure with the authority and title of King of that Province was performed at his own Court, in the presence of St. Breanan of Clonfert, and of his domestic poet MacLemein, who afterwards became first bishop of Cloyne; and also by the concurrence of Aodh Dubh, son of Criomthan, then chief representative of the Eugenian race." He had two sons: 1. Cathal; 2. Congall, the ancestor of O'Noonan, of Thomond and South Connaught.
97. Cathal: the elder son.
98. Turlogh: his son; b. 641. Had—1. Maithan; 2. Ailgeanan, who was the ancestor of O'Meara, Scanlan and MacArthur.
99. Maithan: son of Turlogh; b. 683.
100. Anluan: his son.
101. Corc: his son.
102. Lachtna: his son. Had his residence at a place called Grinan Lachtna, near Killaloe: he d. at an advanced age.
103. Lorcan (also called Fingin): his son; was King of the Dalcassians; d. 942. Had three sons:— 1. Cineidi; 2. Cosgrach, the ancestor of Cosgrave of (Munster), and O'Hogan; 3. Lonargan, a quo Lonergan; 4. Congal; 5. Bran Fionn, a quo Slioght Branfionn, in Wexford: a sept who took the permanent sirname of O'Brien, from this Bran, when sirnames were introduced into Ireland.
104. Cineadh (or Cineidi), King of Thomond : the son of Lorcan; m. Babhion, dau. of Arcadh, son of Murrough O'Flaherty, lord of Iar Connacht or West Connaught.
105. Brian  Boroimhe [Boru], the 175th Monarch of Ireland: a younger son of Cineadh; b. 926, at Kincora, the royal seat of his ancestors; and fell by the hand of Brodar, the Danish admiral, at the Battle of Clontarf, on Good Friday, the 23rd April, 1014, in the 88th year of his age. This Brian ("Brian:" Irish, very great strength), was the ancestor of O'Brien, Kings of Thomond. He had eleven brothers, of whom only four left issue, viz.— 1. Mahoun, the eldest brother, who was King of Munster, before Brian, and a quo many families. II. Donchuan, who was the ancestor of, among other families, Eustace, O'Kennedy, O'Regan, (of Thomond), O'Kelleher, O'Beollan (or "Boland"), O'Casey, Power, Twomey, etc. III. Eichtigern (a quo Ahearne, Hearne, Heron), who was ancestor of MacCraith, (or MacGrath), of Thomond, etc. IV. Anluan, who was the ancestor of Quirk, etc.
Brian Boroimhe was four times m.; his first wife was Mór (more), dau. of Flan O'Hyne, Prince of Hy-Fiachra Aidhne, in Galway, by whom he had three sons of whom Murrough, who fell at the Battle of Clontarf, was one. Brian was secondly m. to Eachraidh, dau. of Ceaibhall, son of Olioll Fionn, and had: 1. Teige;  2. Donal, who distinguished himself at Clontarf, and was slain by the Siol Murray in a battle fought by the Dalcassians against the Conacians. His third wife was Gormliath, the "Kormloda" of Icelandic history; sister of Maolmora, King of Leinster: and relict of Aulaf, the Danish King of Dublin, to whom she bore the celebrated Sitric, who succeeded his father as King of the Danes of Dublin. By Gormliath Brian had Donogh, the 176th Monarch of Ireland, who was the ancestor of Plunkett, and of the O'Briens of Coonagh, in Limerick, and of Aherlow, in Tipperary; and a daughter Sabh, who m. Cian, who is No. 109 on the "O'Mahony" pedigree, by by whom she had Mathgabhuin, the founder of the family of O'Mahony, in the county Cork. Brian's fourth wife was Dubhcobhla, who d. s. p. 1009; she was dau. of Cathal O'Connor, King of Connaught.
106. Teige: younger son of Brian Boroimhe; m. Mór, dau. of Gilla-Brighid O'Mulloy, Lord of Fircall, in the King's County. (Another authority gives Mór as being the dau. of Melaghlin, son of Maolmora the 51st Christian King of Leinster). Teige was killed in 1022 by his brother Donogh, who thus became King of Munster. Donogh was m. to Driella, dau. of Godwin, Earl of Kent, and sister of Harold II., the last Saxon King of England; after a reign of forty-nine years Donogh abdicated; went on a pilgrimage to Rome, and took the habit of a Monk in the monastery of St. Stephen where he soon after died.
107. Turlogh Mór (d. in 1086, aged 77 years), became King of North Munster on the abdication of his uncle Donogh; m. Mór, the dau. of O'Hyne, of Kilmacduagh, in the co. Galway, by whom he had four sons and a daughter. The sons were—1. Teige, who d. at Kincora, leaving two sons, Murrogh and Daniel. 2. Murtogh, who succeeded his father; carried fire and sword, in A.D. 1101, through Conacht and Tir Conal; marched to Aileach Neid which he burned; and after a reign of 30 years he retired (1116) to the monastery of Lismore to repent of his sins—especially of his violation of the sacred soil of Aileach; he died at Lismore in 1119, leaving: Donal, the Shorthand (whose sons Connor and Lewy fell in battle in 1151); Mahon, ancestor of MacMahon of Corca Bascin, and Cineidi Ochar. 3. Dermod, of whom presently. 4. Donogh, slain in 1103 at the battle of Magh Coba. And the dau. was Mór, who m. Roderic O'Connor the 183rd Monarch of Ireland.
108. Dermod: son of Turlogh Mór; in 1116 succeeded his brother, Murtogh, as King of North Munster; m. Sadhbh, dau. of Teige MacCarthy Mór, Prince of Desmond (see "MacCarthy Mór" pedigree, No. 108), by whom he had issue—two sons, 1. Connor-na-Catharach, and 2. Turlogh. The Princess Sadhbh, on the death of Dermod, m. her cousin Cormac Magh-Tamnagh MacCarthy Mór. Dermod, in 1116, was defeated by the Hy-Niall and their Conacht relatives at Ruadh-Bheithach, near Dunkellin, co. Galway; he d. in A.D. 1120, was interred in Killaloe, and was succeeded by his son Connor, who, dying in 1142, was succeeded by his brother, Turloch.
109. Turlogh: son of Dermod; became King of North Munster in 1142; he m. twice—first, to a dau. of MacCarthy Mór, who d. s. p.; and secondly, to Narait or Ragnait, the dau. of O'Fogarty, lord of Ely-Deisceart (or Eliogarty), in Tipperary, by whom he had five sons: —1. Donal Mór; 2. Murtogh, who d. s. p.; 3. Brian of the Mountain, lord of Ormond;. 4. Dermod; 5. Consaidin or Constantine ("Saidh:" Irish, mildness, gentleness; "in," little), bishop of Killaloe (d. 1194), ancestor of the MacConsidine of the co. Clare.
Teige, uncle of Turlogh, contended with him for the Sovereignty of Munster, and a bloody battle was fought at Cluan-na-Catha, near Ardfinan, in Tipperary, in which Teige was defeated. In the year after, another terrible battle was also fought between Turlogh and Teige and his allies, at Barrymore in Cork, in which Teige was again defeated; upwards of seven thousand fell on both sides, A.D. 1152.
Turlogh, after a reign of 25 years, died and was interred at Killaloe, 7th Nov., 1167, leaving his son Murtogh King of Munster, who was slain in 1168, by the people of Clare, at the instigation of Connor O'Brien; for which his brother Donal, on his accession, fined them 3,000 cows.
110. Donal Mór (d. 1194): son of Turlogh; the last King of North Munster; was m. to Orlacan, dau. of Dermod na Gall MacMorough (by his wife, the dau. of O'Moore, Prince of Leix), and had Mór, who married Cathal Craobh Dearg O'Connor (d. 1224), the 51st Christian King of Conacht, with nine sons: 1. Donogh Cairbreach; 2. Murtogh Dall, ancestor of the Clan Murtogh Dall O'Brien, of Hy-Bloid, in the northeast of the co. Clare; 3. Connor Ruadh; 4. Murtogh Fionn, ancestor of the Clan Turlogh Fionn of the same territory; 6. Donal Conachtach, ancestor of Clan Donal Conaghtaigh, of Echtge, and subsequently of Ara, in the county Tipperary; 7. Brian (surnamed "of Burren"), ancestor of Clan Bhriain Boirnigh; 8. Connor, ancestor of Clan Connor Guasanaigh; 9. Dermod Fiodhnuich, ancestor of the Clan Dermod Fiodhniagh. In 1169, this Donal Mór founded a religious house, afterwards the cathedral church on the site of the existing edifice in Cashel; in 1171, he founded a nunnery in the City of Limerick, but not a vestige of it remains. In 1172, following the example of Dermod MacCarthy Mór, King of South Munster, he made Henry II., King of England, a tender of his submission on the banks of the Suir:—
"Woe worth that hour, woe worth that day,
That cost the freedom of the Gael;
And shame to those who broke the trust,
In them reposed by Inis Fail."
In 1175, Donal, blinded Dermod, son of Teige O'Brien, and Mahon, son of Turlogh, his kinsmen, which act caused the death of Dermod soon after at Castleconnell. In 1176, Donal expelled the Anglo-Normans from the City of Limerick, putting most of Henry II's garrison to the sword. In 1192, he drove the English out of Upper Ormond, Ara, and Coonagh, where they established themselves; and stripping them of the booty they took from the native chieftains.
111. Donogh Cairbreach O'Brien: eldest son of Donal Mór; d. 1242. Was the first of the family that assumed this sirname, and the title of "Prince." Was surnamed "Cairbreach," from his having been nurtured in Hy-Cairbre-Aobha. He erected the palace of Clonroad, near the town of Ennis, and m. Sabia, dau. of Donogh O'Kennedy, lord of Muscry Tire, by whom he had Sabina  (who married Geoffrey O'Donoughue of Killarney), and six sons: 1. Connor; 2. Turlogh; 3. Murtogh; 4. Dermod; 5. Teige Dall; 6. A daughter Slainé, who d. Abbess of Killowen, in the barony of Islands, co. Clare—the foundation of her father in 1190. This Donogh Cairbreach O'Brien founded the abbeys of Corcomroe, in the barony of Burren, co. Clare; Killcooley, in the parish of Slievearadh, county Tipperary; Galbally, in the parish of Galbally, barony of Costlea, co. Limerick; and the Franciscan Monastery at Ennis, co. Clare.
112. Connor-na-Siuddine: eldest son of Donogh; slain at the Wood of Siudan, in Burren, county Clare, in 1268: hence the epithet affixed to his name, and a quo Sidney.  He m. Mór, dau. of MacNamara, lord of Hy-Coileann, and left issue: 1. Teige; 2. Brian Ruadh, ancestor of O'Brien of Arra; 3. Murtogh, who died without legitimate male issue.
113. Teige (d. 1259): the son of Connor; surnamed Caol Uisge: so called from his having (see No. 113 on the "O'Neill," Princes of Tyrone pedigree) attended there to hold a conference with Brian Catha Duin O'Neill, to whom this Teige O'Brien and Hugh O'Connor "granted the sovereignty over the Irish," in 1258, or constituted him Monarch of Ireland. This Teige m. Finola, dau. of Kennedy, son of Kennedy, son of Murtogh O'Brien, and had: 1. Turlogh Mór; 2. Donal, who defeated Mahon, grandson of Donal Conachtach, at the Abbey of Clare, in 1276.
114. Turlogh Mór, the hero of MacGrath's "Wars of Thomond:" the son of Teige; d. at his residence Insi-an-Lasi in 1306. Was m. three times: first, to Sabina (d. s. p.), dau. of Teige MacCarthy, of Dun-Mac-Tomain; secondly, to Orflath, (or Aurnia), dau. of Donal Oge MacCarthy Mór, by whom he had— 1. Brian (ancestor of Siol Bhriain na Geall, of Glen Cean), 2. Murtogh (founder of the houses of Thomond and Inchiquin), 3. Dermod (who left no issue); and the third marriage of Turlogh was to Sabina O'Kennedy, of Muscry Tir, by whom he had two sons—1. Connor, and 2. Donal.
115. Murtogh: second son of Turlogh Mór; d. 1343. Was twice m.: first, to Sarah (d. s. p.) dau. of O'Kennedy, of Ormond; and, secondly, to Edaoin or Edina, dau, of his standard bearer, MacGorman, of Ibrackan, by whom he had three sons: 1. Maithan; 2. Turlogh Maol, ancestor of O'Brien of Bun-Cumeragh, in the county Waterford; 3. Teige.
116. Maithan Maonmaighe, who d. 1369: the son of Murtogh. The epithet applied to him means that he was fostered in "Maonmaighe," near Loughrea. Was m. to Winifred, dau. of O'Connor Corc., by whom he had seven sons: 1. Brian; 2. Connor (who m. Mary, dau. of Teige O'Brien, lord of Coonagh, by whom he had—1. Dermod; 2, Donal, bishop of Limerick; 3. Brian Dubh, the progenitor of O'Brien of Carrigagunnel and Glin, in the county Limerick); 3. Teige Baccach, ancestor of O'Brien, of Ballygarridan; 4. Turlogh; 5. Murtogh; 6. Dermod; 7. Donal.
117. Brian Catha-an-Aonaigh (or Brian of the Battle of Nenagh) who d. 1399: son of Maithan. Was twice m.: first to Slaine, dau. of Lochlan Laidir MacNamara. by whom he had three sons: 1. Teige na Glaoidh Mór (d. s. p.); 2. Mahon Dall, who had Turlogh, who had Brian, the progenitor of Siol Bhriain Debriortha (or the exiled); 3. Turlogh. Secondly, to Margaret, dau. of James Fitzgerald of Desmond, by whom he had Brian Udhar Catha, who was the ancestor of O'Brien, of Eachdroma.
118. Turlogh Bog: a younger son of Brian of the Battle of Nenagh; d. 1459. Was the hero of Glen Fogarty and Ballyanfoil; married Catherine, dau. of Ulick FitzWalter Burke, by whom he had issue: 1. Teige; 2. Donogh-Teige, bishop of Killaloe, who was called "Terence," by Ware; 3. Connor Mór na-Shrona, ancestor of O'Brien, of Sealhendhe, in Clare; 4. Turlogh Oge, who, from his dark complexion, was called "Gilla Dubh," and who was the progenitor of O'Brien, of Ballymacdoody; 5. Mahon, of Kilclaney; 6, Kennedy; 7. Brian Ganeagh; 8. Murtogh Beg.
119. Teige an-Chomhaid, or Teige of the Castle of Chomhad, in Burren, which he erected in 1459 in his father's lifetime: son of Turlogh Bog; d. 146S. He m. Annabella, dau. of Ulick Burke, son of "Ulick of the Wine," of Clanrickard, and had six sons: 1. Turlogh Donn; 2. Donal, whose sons Brian, Connor, and Murtogh possessed the estates known as Tir Briain Cacthnava, Dubh, and Dun-Hogan, all in the co. Clare; 3. Donogh, of Drom-fion-glas, who had four sons—Murtogh, Teige, Dermod, and Brian-na-Corcaidh (who divided his estates of Cahir-Corcrain, and Castletown, amongst his sons: I. Mahon, II. Murrogh, III. Connor, IV. Dermod, V. Murtogh, and VI. Teige-an-Comain); 4. Murtogh Garbh; 5. Murrogh; 6. Dermod Cleireach, of Cacthnava-na-Madara, who had six sons—I. Donall-na-Geall, II. Murrogh-an-Tarman, III. Brian-an Comhlack, IV. Mahon, V. Donogh, VI. Torlogh.
120. Turlogh Donn, who d. 1528: son of Teige-an-Chomhaid; married twice: first, to Joan, dau. of Thomas, eighth Lord Fitzmaurice (see No. 13 on the "Fitzmaurice" pedigree); and, secondly, to Raghnait, dau. of John MacNamara, of Clan Coilcain, and by her had: I. Connor; II. Donogh; III. Murrough, first Earl of Thomond and Baron of Inchiquin; IV. Teige, slain by Pierce, Earl of Ormond; V. Dermod; VI. Margaret, m. to Owen O'Rourke, of the county Leitrim; VII. Slaine, m. to Henry Oge O'Neill, son of Henry, Prince of Ulster; VIII. Fionala, who m. Manus O'Donnell, Chief of Tirconnell.
121. Connor, who d. 1540: eldest son of Turlogh Donn; was twice m.: first, to Anabella, dau. of Ulick Ruadh [Roe] de Burgo, of Clan Ricarde, and had:
I. Donogh Ramhar (or Donogh the Fat).
II. Sir Donal, ancestor of O'Brien of Dough, Newtown, and Ennistymon.
I. Sir Turlogh, lord of Ibrackan.
II. Teige, of Ballinacorrig, whose dau. Amory m. John, Knight of Kerry.
III. Murrogh, of Cahironanane, whose only son, Dermod, died young.
IV. Murtogh, of Dromtyne, whose two sons d. s. p.
122. Donogh Ramhar, the second Earl of Thomond: eldest son of Connor; m. Helena, dau. of Pierce, Earl of Ormond, and had:
II. Donal, ancestor of O'Brien of Ballincorran, in the co. Clare, represented in 1741 by William O'Brien, son of Murrogh-na-Buile.
I. Margaret, who m. Dermod, Lord Inchiquin.
II. Honoria, who m. Teige MacNamara of Clan Coilcain.
III. Mór, who m. Theobald, son of William, the first Lord Castleconnell.
123. Connor, the third Earl: the son of Donogh Ramhar; was twice m.: first, to Joanna, dau. of Thomas, the 16th Lord Kerry, and had a dau., who d. s. p.; and, secondly, to Winifred, dau. of Turlogh O'Brien of Ara, by whom he had:
I. Donogh, of whom presently.
II. Teige, who m. Slania, dau. of Teige, son of Murrough, Earl of Inchiquin, the proprietor of Smithstown Castle otherwise called Ballygowan, and had:
I. Turlogh, of Ballyslattery, who m. the dau. of Donogh O'Brien, of Leamanagh, and had a son Connor.
II. Col. Murtagh, who m. Joanna, dau. of Turlogh MacMahon, of Clena, but d. s. p.
III. Dermod, who m. Una, the dau. of Donogh O'Brien, of Newtown, and d. s. p.
III. Sir Donal, from whom descended the Viscounts Clare; the third son of Connor.
I. Honoria: the eldest daughter of said Connor, the third Earl of Thomond; who m. Thomas, the 18th Lord Kerry.
II. Margaret, who m. James, the second Lord Dunboyne.
III. Mary, who m. Turlogh Ruadh MacMahon.
124. Donogh:  the eldest son of Connor, the third Earl of Thomond; was the fourth Earl, who was commonly called the "Great Earl;" d. Sept., 1624; m. Elizabeth, dau. of Gerald, the eleventh Earl of Kildare, and had:
I. Henry, the fifth Earl, who m. Mary, dau. of Sir William Brereton, Baron of Leighlin, and dying in 1639, left:
I. Mary, whose first husband was Charles Cockaine, first Viscount Cullen.
II. Margaret, who was the second wife of Edward Somerset, Marquis of Worcester.
III. Elizabeth, who was the second wife of Dutton, Lord Gerard, of Bromley.
IV. Anne, who m. her cousin-german Henry, the seventh Earl of Thomond.
V. Honoria, who m. Henry, Earl of Peterborough.
II. Brian, the sixth Earl, of whom presently.
125. Brian, the sixth Earl of Thomond: the second son of Donoch.
126. Henry, the seventh Earl: his son; m. twice: first, his cousin-german, Anne, as above mentioned, and had:
I. Henry, Lord of Ibrackan, who m. Catherine Stuart, sister of the last Duke of Richmond and Lennox, of that House, and had:
I. Donogh, who m. Sophia, dau. of Thomas Osborne, Duke of Leeds, but d. s. p.
I. Mary, who m. Robert, the 17th Earl of Kildare.
II. Catherine, who m. Edward Hyde, Earl of Clarendon.
Henry, the seventh Earl of Thomond, was secondly m. to Sarah, daughter of Sir Francis Russell, of Chippenham, and had:
III. Henry, who d. young.
IV. Another Henry.
III. Elizabeth, who d. s. p.
IV. Finola, who was the first wife of Henry Howard, Earl of Suffolk.
V. Mary, wife of Sir Mathew Dudley, of Clopton.
127. Henry Horatio, Lord O'Brien, and Baron of Ibrackan: youngest son of Henry, the seventh Earl; d. 1690, vita patris; m. Henrietta, dau. of Henry Somerset, Duke of Beauford, and had:
I. Henry, of whom presently.
128. Henry O'Brien: the son of Henry Horatio; succeeded his grandfather as the eighth Earl of Thomond. He m., in 1707, Elizabeth, dau. of Charles, Duke of Somerset; was created an English Peer by the title of "Viscount of Tadcaster," in 1714; and d. without legitimate male issue, on the 20th of April, 1741.
 Stem: Along with the Stem, the genealogies of the following branches of this family are also contained in this Volume: 1. O'Brien, of America; 2. of Ara; 3. of Dough; 4. of England; 5. of Ennistymon; 6. of Lords of Inchiquin; 7. of Marquises of Thomond; 8. of O'Brien of Newtown; and of Viscounts Clare, etc.
 Thomond: The place of inauguration of the O'Briens, as Kings and Princes of Thomond, was at Magh Adhair, a plain in the barony of Tullagh, county of Clare; and their battle-cry was Lamh Laidir An Uachdar, or "The Strong hand Uppermost." On their armorial ensigns were three lions rampant, which were also on the standards of Brian Boroimhe, borne by the Dalcassians at the battle of Clontarf. In modern times the O'Briens were Marquises of Thomond, Earls of Inchiquin, and Barons of Burren, in the county of Clare; and many of them were distinguished commanders in the Irish Brigades in the service of France, under the titles of Earls of Clare, and Counts of Thomond.
 Brian: Brian Boroimhe is represented by our old annalists as a man of fine figure, large stature, of great strength of body, and undaunted valour; and has been always justly celebrated as one of the greatest of the Irish Monarchs, equally conspicuous for his mental endowments and physical energies; a man of great intellectual powers, sagacity, and bravery; a warrior and legislator; and, at the same time, distinguished for his munificence, piety, and patronage of learned men: thus combining all the elements of a great character, and equally eminent in the arts of war and peace; a hero and patriot, whose memory will always remain famous as one of the foremost of the Irish Kings, in wisdom and valour. Brian lived at his palace of Cean Cora (Kincora), in a style of regal splendour and magnificence, unequalled by any of the Irish Kings since the days of Cormac MacArt, the celebrated Monarch of Ireland in the third century—the glories of whose palace at Tara were for many ages the theme of the Irish, bards.—CONNELLAN'S Four Masters.
Oh, where, Kincora! is Brian the Great?
And where is the beauty that once was thine?
Oh! where are the Princes and Nobles that sate
At the feast in thy halls, and drank the red wine.
Where, oh, Kincora!
 Teige: In O'Farrell's Linea Antiqua, on the "Roll of the Monarchs of Ireland," at No.178, this Teige is mentioned as the "eldest" son of Brian Boroimhe.
 Sabina: This Sabina, her husband, his brother, and three of Sabina's sons, were burned in their own house at the "Green Ford," by Fingin Mac Conal MacCarthy.
 Sidney: From another authority we learn that the cognomen of this Connor should be written Suiderly or "of the spittles;" and the fact of his effigy having a short pipe in its mouth gives support to this conjecture: hence it is clear that the Irish smoked in the twelfth century!
It is also stated that Connor was slain by his own Kinsman, Dermod, son of Murtogh O'Brien, whereupon Brian, son of Connor, was nominated "The O'Brien." Connor was interred in the north end of the abbey of Corcomroe, where the peasantry still point out the site of his tomb. On the tomb in bas-relief is the effigy of a mailed warrior in the usual recumbent posture, wearing the round tunic of the 13th century, and a short pipe in his mouth.
 Donogh: In 1601, this Donogh O'Brien, the fourth Earl of Thomond, assisted the English against the Irish and Spaniards at Kinsale. He commanded a thousand men, chiefly English, and the defeat of the native Chiefs and Princes was owing in a great measure to the bravery which he displayed. It is stated by Carew, in the Pacata Hibernia, that Donogh had often told him that an Irish prophet, whose writings he had often read, foretold the defeat of the Irish at Kinsale; and Fynes Morison says that the Manuscript containing the said "prophecy" was shown to Mountjoy on the day of that engagement. On the 6th May, 1605, Donogh was appointed President of Munster; and Commander-in-chief of the English forces in that Province, on the 25th of the same month, in that year. He died on the 5th of September, 1624, and was interred in the Cathedral Church of Limerick, where a handsome monument, exhibiting a Latin inscription, was erected to his memory.