Connor O'Brien, King of Thomond (fl. 1528 until his death in 1540) was the second to last King of Thomond.

Connor was the eldest surviving son of Turlogh-Donn inaugurated King of Thomond in 1498 (and grandson of Teige-an-Chomhaid), and Raghnait, daughter of John MacNamara chief of the MacNamara clan

Clan MacNamara

Mac Conmara is the surname of a family of County Clare in Ireland. It is anglicised MacNamara or McNamara-Background:The name means "Hounds of the Sea"...

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In 1528, on the death of his father Connor was inaugurated King of Thomond and having reigned for 12 years he died in 1540. His eldest son Donough

Donough O'Brien, 2nd Earl of Thomond

Donough O'Brien, 2nd Earl of Thomond , also known as "the fat", was the son of Connor O'Brien, King of Thomond and Annabell Burke.O'Brien married Helen Butler, daughter of Piers Butler, 8th Earl of Ormonde and Lady Margaret Fitzgerald. Donough O'Brien died on 1 April 1553, after being attacked by...

 was a minor when his father died and Connor's brother Murrough

Murrough O'Brien, 1st Earl of Thomond

Murrough O'Brien, 1st Earl of Thomond was the last King of Thomond.A member of the Irish nobility, he was the son of Turlough O'Brien, King of Thomond and Raghnailt McNamara and also brother of Connor O'Brien, King of Thomond, who was inaugurated King of Thomond in 1528...

 gained the estates and title of King of Thomond under tanistry, or popular election (then in general use, but abolished by King James in 1605) whereby the estate and title were to descend, for life, to the eldest and worthiest man of the blood and name of him that died last.

Both parties appealed to Henry VIII

Henry VIII of England

Henry VIII was King of England from 21 April 1509 until his death. He was Lord, and later King, of Ireland, as well as continuing the nominal claim by the English monarchs to the Kingdom of France...

 and it was agreed that Murrough would become the 1st Earl of Thomond and upon his death the title would pass to Donough, on condition that both men recognised Henry as their lawful king, that they would give up their claims to be King of Thomond and that they would become Anglican. This arrangement was agreed, and with the death of Murrough the title of Earl passed to Donough. However on the death of Donough in 1551, the rights of his son, Connor, 3rd Earl of Thomond

Connor O'Brien, 3rd Earl of Thomond

Connor O'Brien, 3rd Earl of Thomond , called Groibleach , grandson of Conor O'Brien ; succeeded to the earldom, 1553; his right to the lordship of Thomond was disputed by his uncle, Donnell; confirmed in his possessions by Thomas Radclyffe, 3rd Earl of Sussex in 1558, who proclaimed his uncles...

, to the title and estates was challenged by Donnell, his uncle and a brother of his father, who was inaugurated O'Brien and chief of the Dal Cais. Donnell appealed to Queen Mary

Mary I of England

Mary I was queen regnant of England and Ireland from July 1553 until her death.She was the only surviving child born of the ill-fated marriage of Henry VIII and his first wife Catherine of Aragon. Her younger half-brother, Edward VI, succeeded Henry in 1547...

 (a Roman Catholic) to uphold his usurpation. After many years of family and civil strife Connor secured his position and lands in the late 1570s during the reign of Queen Elizabeth

Elizabeth I of England

Elizabeth I was queen regnant of England and Ireland from 17 November 1558 until her death. Sometimes called The Virgin Queen, Gloriana, or Good Queen Bess, Elizabeth was the fifth and last monarch of the Tudor dynasty...

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Family

Connor married Anabella, youngest daughter of Ulick De Burgh, (the red) of Clanrickard. They had two children:

• Donough
  Donough O'Brien, 2nd Earl of Thomond
  Donough O'Brien, 2nd Earl of Thomond , also known as "the fat", was the son of Connor O'Brien, King of Thomond and Annabell Burke.O'Brien married Helen Butler, daughter of Piers Butler, 8th Earl of Ormonde and Lady Margaret Fitzgerald. Donough O'Brien died on 1 April 1553, after being attacked by...
  
  , (the Fat) his heir;
• Sir Donald.

Connor's second wife was Ellice, daughter of Maurice née Baccagh, Earl of Desmond. They had four sons: *Sir Turlogh, took possession of the lordship of Ibrackan, and dying soon after, had two sons, who died childless);

• Teige, held the lordship of Ibrackan after his brother's death, until his half brother Sir Donald and he were expelled. His inheritance was Ballynocorrig, and he gave rise to the family of that place; having also a daughter Amory, married to Shane, knight of Kerry;
• Murrough of Cahironenane, whose son Dermod died young;
• Mortogh of Dromtyne, whose two sons left no issue.