The name of O'Brien in Ireland is of great antiquity going back to the 14th century when Richard II knighted Brian O'Brien who became the Earl of Thomond. Descendants of this family established themselves in Co Carlow in the early 17th Century (3).   "A Grant of the office of Constable of Carlow Castle was given to Donogh, Earl of Thomond and Brien O'Brien his son in 1604" (4)   (Note: I cannot find any history that names a Brien O'Brien as the son of Donough Earl of Thomond so this may be an error by the author.  The 4th Earl of Thomond had a son Barnaby O'Brien (2nd son))
.My ancestor, Brien O'Brien of Garryhill, Co. Carlow, lived in Garryhill, Co. Carlow but I have no proof that he descended from the Earls of Thomond.


Brien O'Brien of Garryhill,  is known to have had at least three children. The eldest being born about 1721. It is therefore surmised that Brien O'Brien would have been married about 1720 at the age of about 25 meaning his birth year was probably circa 1695. No records of his marriage have been found. As his eldest son was given the middle name Perkins it is highly likely that Brien's wife was a Perkins.

Brien O'Brien's children:

• a daughter (no information)

• Catherine O'Brien 1721-1804. Married Francis Dillon  who was the second son of Thomas Dillon of Park. He died intestate on 13th Nov. 1780 from a fall from his horse when out hunting. Catherine (O'Brien) Dillon was granted a Bishop's lease of Old Leighlin on 30 Jan. 1802. She died aged 82 on 23 March 1804 (will dated 16 Feb. 1802, proved 16 June 1804) and was buried in a vault in Carlow Church on 25 March.They had three sons:
• Edward Dillon,
  
• James Dillon, died unmarried
• Francis Dillon (Married Catherine O'Brien) .
  

• John Perkins O’Brien.  Born about 1725 in Garryhill, Co Carlow. Attended Ballitore School.  No record of a marriage. He was appointed Church Warden of Dunlecky Parish Church in 1792 and died after 1794. Described in the marriage settlement for Anne O'Brien and Thomas Bernard as "the older brother of Arthur O'Brien"

• 

• Arthur O'Brien. Born about 1730 He married Mary Perkins of Ballintrane in 1767. 

• Anne O'Brien, probably born circa 1770, married Thomas Bernard in 1790 (1)
• Catherine O'Brien (described as second daughter, at the time of her marriage) b. about 1773 married in 1795 Francis Dillon b. 1760, of Garryhill . No children.  Francis was the 3rd son of Francis Dillon and Catherine O'Brien (sister of Arthur O'Brien)  (2)
  

        Arthur died after 1782, his will was probated in 1786.

In another record from the Chancery Court in 1782 the relationship between the O'Brien and Perkins family is shown as some are plaintiffs and some are defendants.

The case names two of the daughters of John Perkins and their husbands and children as plaintiffs and the other daughters and several O'Briens as defendants.

Plaintiffs: James Garrett Esq.and Jane [Perkins] his wife; John, Anne, Jane and Joanna their children; Thomas Whelan Esq. Joanna [Perkins] his wife, John and Priscilla Whelan their children.



Defendants: Benjamin Hobart, John James, William Evans and Anne [Perkins] his wife, Samuel Brewster and Marian his wife, Elizabeth [Perkins] Flood  widow, John Henry and Perkins Flood. Frances and Mariana Flood. Arthur O'Brien and Mary [Perkins] his wife. Brian O'Brien, Ann, Mary, Elizabeth and Margaret O'Brien.. Note: It is not know who this Brien O'Brien and Ann, Mary, Elizabeth and Margaret O'Brien are.


A will for Brien O'Brien of Garryhill was registered in 1763. No date of death has been found.  No record of the death of his wife has been found.

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Did Brien O'Brien have a son also called Brien O'Brien?  There are no records that confirm this but there are clues:

• In the Chancery Court in 1782 (above) Brien O'Brien is mentioned as a defendant. Above his name are Arthur O'Brien and John Perkins O'Brien. Are they his older brothers?  Neither Arthur or John Perkins O'Brien had a son. 
• Bryan O'Brien of Garryhill leased two properties to farmers in Garryhill in 1801. Two of the witnesses were Francis Dillon and John Perkins O'Brien. (7) and (8)
• A Brien O' Brien and his son Brien O'Brien (Jun) who lived in Ballinvally, took the Oath of Allegiance 1797 (5)  Also in 1797 a Brien O'Brien of Ballinvally leased lands to John Power a farmer of Boggan.(6) It is possible that Brien O'Brien of Ballinvally is the same Brien O'Brien who is leasing Garryhill properties to farmers in 1801. Ballinvally and Garry Hill are about 12 km. from each other. He could have been living in Ballyvally but still held property in Garryhill.
  
• Below Brien O'Briens name in the Chancery Court record of 1782 are Anne O'Brien, Mary O'Brien, Elizabeth O'Brien and Margaret O'Brien. Although Arthur O'Brien and his wife Mary (Perkins) O'Brien had a daughter Anne (who married Thomas Bernard), they are not known to have had any other children.  Could Anne, Mary, Elizabeth and Margaret O'Brien be the children of Brien O'Brien? 
• In a deed dated 1812. William and Mary O'Brien assigned a a lease on a property in Carlow to Benjamin Spencer, that had been previously leased to Brien O'Brien.(9)
  

References:
Registry of Deeds: Vol #, Page #, Memorial #
(1)   Memorial 443/174/285665 Image # 383
(2)   Memorial  498/310/319081    Image# 400
(6)    Memorial  509/288/331788   Image # 158
(7)   Memorial   531/386/357452    Image # 497
(8)   Memorial     531/387/357453   Image # 497
(9)   Memorial    64/424/446672   Image # 505
To find the Memorial go to Registry of Deeds Index Project Ireland. Insert Volume and Image #

(3)   Carlow History and Society. Ed. Thomas McGrath
(4)   History and Antiquities of the County of carlow. John Ryan
(5)   http://www.igp-web.com/Carlow/Oath_1797_1.htm