The claim that the 1st Baronet had a daughter Catherine 
 See the  
  proof of our Blennerhassett descent.
This  suggests  our family  most likely descends from  
Sir Rowland Blennerhassett, 1st Baronet.
Our family story was that we descend from a runaway Blennerhassett daughter.
 
So I am   keen to establish if  the 1st Baronet  had a daughter.
In the past, there were 
 claims  that
he had a daughter Catherine.
This  is clearly an error.  
  
  
  The printed histories 
 The printed family histories such as Debrett's and Burke's 
at one point showed a Catherine.
But this is clearly  an error. 
 
 
The 1st Baronet has no daughter in 
the  entry for Blennerhassett 
in   [Debrett's Baronetage, 1815].
This is 
on p.1247
of vol.2.
The genealogy  has errors  ("Harley" for Hurly). 
 
 
The 1st Baronet has no daughter on
p.1178
of vol.2 of
    [Debrett's Baronetage, 1819].
 
 
In    [Debrett's Baronetage, 1824],
the 1st Baronet is now  listed with a daughter  Catherine.
From   p.1115
of vol.2. 
 -  This edition is a bit out of date. The 1st Baronet died in 1821. 
- 
In the entry, the 1st Baronet's   daughter 
Catherine     marries Rev. Edward  Conyers, of "Knockmare".
 
- 
Knockmare  however is  not a CoI parish.  
-  
This  is clearly     confusion  with Catherine,
  dau of the  2nd Baronet, who had just 
married in 1822  to 
Rev. Edward Fitzgerald  Conyers,
of Castletown Conyers,  
  now 
Rector of Knockane,
Co.Kerry.
 
-  This edition  does not yet  list the children of the 2nd Baronet. 
  
  
 
 
 
   
 
The 1st Baronet is  still   listed with a daughter  Catherine  
on 
p.628 
of vol.2 of 
  
 [Debrett's Baronetage, 1828]. 
 
 
-  In this edition,    Debrett's  now  also   lists   Catherine, dau of the 2nd Baronet. 
That is, it
 lists both    the 1st Baronet and the 2nd Baronet with a dau Catherine  who marries a Rev. Edward Conyers.
 
-  The 2nd  Baronet's   daughter is listed correctly, with the correct middle name and origin.
It does not list his parish. 
-   In the entry, the 1st Baronet's   daughter 
Catherine     marries Rev. Edward  Conyers, of "Knockman".
 
 
- 
Knockman however is  not a CoI parish.  
-      
 [Ardfert and Aghadoe Clergy] 
also  says there is only one Rev. Conyers in Co.Kerry, the one of Knockane 
who married the daughter  of the 2nd Baronet.
-  It is clear the 1st Baronet has no daughter Catherine  and this is just an error. 
 
  
    19th century  printed  sources   duplicate this 
  
 
  
 Late 19th century on: The printed sources correct  this 
Starting in the late 19th century, the printed  histories seem to have  decided this "Catherine" 
was an  error  
 and removed her.
-  Foster  removes this "Catherine". 
The 1st Baronet  is   on
p.574
of 
  [Foster's Royal Descents, vol.4, 1886]
and  it shows   no daughter.
  
 
-        [Burkes Peerage, 1894, p.144]  
still lists  
both the 1st Baronet and the 2nd Baronet with a dau Catherine who marries a Rev. Edward Conyers.
- 
[Lodge's Peerage, 1903] and
[Lodge's Peerage, 1912] 
are still listing   the 1st Baronet  with 5 sons and   "other issue".
-        [Burkes Peerage, 1912, p.244]  
has now  removed the 1st Baronet's daughter   "Catherine".
 Later editions  show no daughter for the 1st Baronet.
They    show only the 2nd Baronet with dau Catherine.
 
-  See extract 
from    [Burkes Peerage, 1959].
The 1st Baronet has no daughter.
-  Mercifully, the error appears to be finally dead. 
Even a search on Ancestry trees
does not turn up this   error.
 
 
  
      Records of Ballingarry  
 
More  confusion  was caused by  a   misleading   extract from  the book 
  
Records of Ballingarry.
 
 
 Catherine Blennerhassett, born 1788, daughter of "Sir R. Blennerhassett". 
From  
  Limerick City Library
extracts 
 from  the book  
Records of Ballingarry 
 [Hamilton, 1930].
 
 If she really was born 1788, this would be a dau of the 1st Baronet,
 not the  2nd Baronet  (who married 1790).
 
   

 
When we look at the original source in [Hamilton, 1930] though, 
we see  the extract is misleading.
 The extract makes it look like it  is an original  baptism entry.
But it is not. It is just an extract from a set of family notes in the book.
  In the original notes, 
Catherine is discussed as the person who married Rev. Edward Conyers
 and was born 1788 and died 1869. 
This context  is lost when making the extract of BMD.
 
So there is no new Catherine.
The date 1788 is simply an error.