This Duke has a pedigree on the LDS family history website and it goes all the way back to the Lincolnshire Ormsbys in the days of William the Conquerer.
This same geneology (at least as far as Edmond in 1558) appears on the Ormsby.net website but it has been taken from a book that was taken from a book, so I’m not sure who has their dates wrong.
According to LDS, the first Ormsby to leave England, Thomas, was married in Ireland in 1556, but according to the Ormsby.net website (as well as a reference to an ‘Elizabethan settler’ on the Irish Landed Estates site) he didn’t arrive in Ireland until the reign of Queen Elizabeth, which didn’t start until 1558. I believe both these sites are pulling from JF Fuller, but I can’t be sure until I see his book for myself. The LDS site of course, gives no information about sources nor any verification of accuracy, so if I have to believe one or the other, I’d believe Fuller.
I don’t see why Thomas (a protestant) would leave England to go Ireland until England had a protestant queen. (Back in those days, migrations to Ireland were encouraged by protestant royalty to ensure that the Catholics were kept under control). But for the 5 years prior to Elizabeth’s reign, Mary ruled Ireland and England and was far less favorable to protestants (to put it lightly!)
How do I know Thomas was a protestant? Because:
He married a daughter of Henry Malby, son of Sir Nicholas Malby, chief commander of the English forces in Connaught in the time of Queen Elizabeth. Ref.: “The English in Ireland in the 18th Century” by James Anthony Froude.
I don’t think Malby’s grandaughter would have been allowed to marry a Catholic.
But even if some of the dates seem wrong, the lineage definitely ends with a Duke Ormsby, born in Annagh around 1668. His father was Philip Ormsby, who is supposed to have lived between 1616 and 1694.
And this makes me wonder about a document I found online. Other than the LDS mention, this is the first mention of a Duke Ormsby that I have found. The document is the story of battle between protestants loyal to King William and Catholics supporting James 1st. It’s title is “A BRIEFE ACOUNT OF THE PROTESTANTS ASSOCIATING AT SLIGO VNDER THE COMMAND OF THE RIGHT HONBLE ROBERT LORD BARRON OF KINGSTON AND THE HONBLE CHIDLEY COOTE ESQR. THE 4TH DAY OF JANUARY 1688.” You can read the whole thing by clicking here, but here’s a screenshot of the list of soldiers, including a Cornet Duke Ormsby:
Could that be the same Duke? A Cornet was an entry-level officer, if I understand correctly so he’d be about the right age (20). There’s also a captain Philip Ormsby, which may have been his father. But there are also several other Ormsbys, all listed as officers, which makes me think that, whether or not this is the Annagh Duke or another Duke, they were a prominent family and had a strong bond of loyalty to the English power structure. Perhaps because Thomas had been given land when he moved from England?