The Blennerhassett problem

There has been one epic problem in all of my family tree research - the Blennerhassett problem. This is the problem of how we descend from the Blennerhassett family. I first became aware of our possible Blennerhassett descent in 1985. It took me 35 years to prove it. In 2020, DNA testing finally proved that we descend from the Blennerhassett Baronets branch.

See Proof of our descent from Blennerhassett for the proof that we descend from the Blennerhassett Baronets branch.

I call it as proved that my ancestor George Cashel (born 1807) descends from Robert Blennerhassett (died 1765) and his wife Frances Yielding. Nothing else explains the DNA.

That we descend from this family is proven, but the exact descent is unproven. The story in our family is that George Cashel's mother was "Letitia" Blennerhassett. However no such Blennerhassett girl has been found. The family memory may be confused, but DNA says that some descent from this family definitely exists.

The exact link to the Baronets family is unknown. It remains to prove this from paper, to confirm from paper records what the DNA says must exist.

I am trying to prove a story from 1807. That is, 218 years ago.

Summary of DNA findings: The older Cashel family matches the Blennerhassett Baronets

That our family is connected to some Blennerhassetts was never in doubt. But which Blennerhassetts? There were paper clues that we might be connected to Letitia Blennerhassett of Tarbert, and other paper clues that we might be connected to the Blennerhassett Baronets. But it is the DNA that proves it. Using both Ancestry and Gedmatch, we found strong DNA matches of the older Cashel family with the Blennerhassett Baronets family.

In the following, DNA matches are measured in centimorgans (cM). Of the Cashel family members for whom we have DNA, of the ones that are closest to the origin of the family (4th or 5th cousins of people outside the family):

3 out of 14 of them have DNA matches of 9 cM or more with the Letitia Blennerhassett of Tarbert family.
11 out of 14 of them have DNA matches of 9 cM or more with the Blennerhassett Baronets family.

If you push the bar for a match a little higher:

1 out of 14 of them have DNA matches of 10 cM or more with the Letitia Blennerhassett of Tarbert family.
9 out of 14 of them have DNA matches of 10 cM or more with the Blennerhassett Baronets family.

The Letitia matches are few and go up to 11 cM. The Baronets matches are numerous and go up to a staggering 24 cM. We also have specific matches with the wives of the Blennerhassett Baronets, showing it really is that branch.

The lack of Letitia matches shows that the Baronets matches are not by chance. If you pick a family at random, you will not get matches. They have to be close relations or you get no match. In fact, the Letitia family are even known relations of the Baronets family, but not close enough to get good matches.

The Letitia of Tarbert theory is false.
The Blennerhassett Baronets theory is true. We really are closely related to the Blennerhassett Baronets family.

George Cashel's RIC record.
Showing that he was recommended by "A. Blennerhasset, J.P." when he joined the County Constabulary in 1828.

George Cashel is written "George Blennerhassett Cashel" on the marriage cert of his son Blennerhassett Cashel in 1869.
See full size.

Detail from grave of George Cashel's son Blennerhassett Cashel.

The parents of George Cashel are not that far back.
They are Ahnentafel number 88 and 89 (if I am number 1).
There are 64 people in that generation, numbered 64 to 127.

The search from 1985

The Blennerhassett descent in the notes of my grand-aunt Pat Lavelle.
Pat died in 1966, before I was born.
I discovered her notes in 1985, and set off to prove the Blennerhassett descent.
It took me until 2020 to prove it.

This brief note in the BLENNERHASSETT entry in [Burkes Irish, 1976] by Brian Fitzelle first made me realise in 1985 that my Blennerhassett line might connect to the World family tree.

U2 at Live Aid in 1985 - the summer when my lifelong quest for Blennerhassett began.

Me at New Ballyseedy in 1985, at the start of the life-long hunt for Blennerhassett.
It later turned out that my ancestors never lived in this building.

Me at the rear of Blennerville House in 2022.
This is probably my actual ancestral home.

According to the Baronets theory (which seems to be true) my ancestors did not live at New Ballyseedy. They lived at Ballycarty and Old Ballyseedy and Castle Conway (all in ruins) and (if we descend from the 1st Baronet, which is likely) Stephen St, Dublin (unknown house, might survive) and Blennerville House (survives) and Churchtown House (survives).
According to the Letitia of Tarbert theory (which I have abandoned) my ancestors did not live at New Ballyseedy either. Under that theory, they would have lived at Ballycarty and Old Ballyseedy and Castle Conway (all in ruins) and Tralee Castle (demolished 1826) and Tralee Rectory (demolished 1995).

Letitia Blennerhassett in popular culture

Due to my friendship with the cartoonist and artist John Chambers, a mythical version of our supposed ancestor "Letitia Blennerhassett" has entered popular culture. John has followed the Letitia Blennerhassett story since the 1980s, and, loving her name, has included her in various of his creations.

Post, 23 Jan 2013, by Granny Samurai on Facebook.
"Granny Samurai in her Sunday Bonnet. She took First Prize on ladies day at Ascot. Just grabbed it right out of Laetitia Blenner-Hasset's lobster-like grip. Megawocka!"

John writes a joke letter to the Financial Times in 2008.
"How the Emerald Isle was turned blue" (and here), Financial Times, 22/23 Mar 2008.
"During his years in Japan (1891-1904), Lafcadio Hearn corresponded with a scholarly neighbour of his back in Ireland, one Letitia Blennerhassett. Though largely forgotten today, she was in her time a formidable scholar of the Irish language, collecting and translating a great deal of folk tales that would otherwise have been forgotten."
This letter was published, but the data is entirely made up.

The lost baptism

One fundamental lost document, that could easily have survived, is George Cashel's baptism around 1807.
I suspect he was baptised CoI in Co.Kerry, probably near Churchtown House.
But unfortunately the majority of Co.Kerry CoI parish records from the 1807 period were burnt in 1922, including records of the church he was most likely baptised in, Killarney CoI church (near Churchtown House).

Above is an evocative survival:
An 1806 baptism for a "George Supple" in Tralee CoI church.
If the baptism record had survived for George Cashel, it would explain who his parents were.
I suspect it was burnt in 1922.

Above is another evocative survival:
The baptism on 6 September 1799 in Killorglin RC church of Arthur Murphy.
He is the grandson through illegitimacy of Arthur Blennerhassett of Fortfield, brother of Sir Rowland Blennerhassett, 1st Baronet.
DNA says George Cashel is closely related to this family, almost certainly also through illegitimacy. But all efforts to find George's baptism have failed.

The lost census

Another lost document, that could easily have survived, would be the 1821 census.
George Cashel was age 14 in 1821, and the census could explain who his parents were, or maybe just who his mother was.
But unfortunately almost all of the 1821 census was burnt in 1922, including the whole census for Kerry.

Above is an evocative survival:
The 1821 census entry for a 15 year old "George Reilly" and his family in Co.Cavan.
This could have survived for 14 year old George Cashel, explaining who one or both of his parents were.
But it was burnt in 1922.

AI images and video

AI animation of a photo of Blennerhassett Cashel.
Made using Deep Nostalgia at MyHeritage.
If only I could ask him who his grandparents were!

Some fun AI image generation to imagine the moment of finding the documentary proof of George Cashel's parents.
I used this program by one of my students, Darragh McGonigle, to interface with DALL-E 3 by OpenAI.
I asked it to generate an image for: "man ecstatic after manuscript discovery in library".
It automatically "enhanced" the prompt to: "A jubilant Caucasian man holding a discovered, ancient manuscript in a traditional library setting. He's standing by towering wooden bookshelves filled with aged books. His face is brimming with excitement, caught in that precise moment when his fingertips first touched the parchment. His glasses are slightly slipping down his nose, adding a quirky charm to his scholarly appearance. Soft library lights cast an inviting glow on the scene, highlighting the worn-out textures of countless knowledge repositories surrounding him. Hints of dust particles in the air contribute to the evocative atmosphere."
This image is the result.

My link to medieval Ireland

My link to medieval Ireland and England was burnt in 1922, and rediscovered by me in 2020.

The Public Record Office, Dublin, before it was burnt by Irish "patriots" in 1922.
The 1821 census would probably have solved the Blennerhassett problem immediately, by explaining who 14 year old George Cashel's parents were.
But it was burnt in 1922. My link to medieval Ireland was broken for most of my life, because of Irish "patriots".
They burnt the 1821 census, 1831 census, 1841 census and 1851 census.
See larger and full size.
From here.