De Leon or Dillon family from Brittany, Normandy

I'm sure there is a lot more out there than what I have to offer at the moment, but it's pretty interesting, imho.

Dillon, or De Gamaches. The Lords of Gamaches, in the French Vexin [Normandy], were said to be descended from Protadius, Mayor of the Palace to Theodoric, King of Orleans, [604 (Des Bois)]. A branch became seated in England, and Godfrey de Gamaches, who held two fees from Hugh de Lacy, of Hereford 1165, was granted the '''barony of Dylon or Dilion''', in the same county, by Henry II. 1158. His grandson,
Matthew de Gamache(3), was Baron of Dylon, and on his forfeiture as a Norman, William de G[amache or Gamage]., his brother, had a grant of the barony 1217. He
had Adam and Henry, the latter of whom passed into Ireland, and was ancestor of the Earls of Roscommon, Viscounts Dillon, and Lords Clonbrock.

https://babel.hathitrust.org/cgi/pt?id=mdp.39015066917595&view=...

Sir Godfrey de Gamache (Arnold)

Coincidentally, he's my 29th g-grandfather. :D

I would suggest try googling "Dilion", "Dillion", "Dylon", "Dylan", and/or "De Lion" as variations on the surname. Also logically there ought to be some Dillon surnames among the descendants of Sir de Gamache (above).

Theobald Dillon, 1st Viscount Dillon of Costello-Gallen mentioned in official Parliamentary records, here (p. 178 onward):

https://books.google.com/books?id=-0oSAAAAYAAJ&pg=PA178&lpg...

Another link to it, in case the first one doesn't work:

https://www.google.com/books/edition/_/-0oSAAAAYAAJ?hl=en&gbpv=...

https://en.wikipedia.org/wiki/Theobald_Dillon,_7th_Viscount_Dillon

Many references to Dillon on British History Online:

https://www.british-history.ac.uk/search?query=dillon

https://www.british-history.ac.uk/cal-state-papers/colonial/america...

"P.S.—I am to be found at George Purrice on ye long branch of Rappahannock river in Spotsylvania Country. Signed, James Dillon."

(Dated July 1735, Virginia)

There are several James Dillons on Geni and I didn't look at all of them, but this one is the son of a William Dillon who immigrated from Kerry, Ireland, to Virginia Colony.

James Dillon

James Dillon, among other Dillons, were included among the proprietors of estates that were confiscated in 18th century Ireland. Also, beginning on p. 56, there is a detailed history of the Dillon family in Ireland. ''The Irish Landed Gentry by John O'Hart":

https://babel.hathitrust.org/cgi/pt?id=iau.31858050739550&view=...

https://babel.hathitrust.org/cgi/pt?id=iau.31858050739550&view=...

THE “DILLON” FAMILY, Barons of Drumrany.

"THIS noble family, according to Lodge, one of the best recognised genealogists of the last century (see Lodge's Peerage, vol. IV., p. 135), is said to derive its origin from Lochan or Logan **Delune**, or **Delion** (a descendant of one of the Monarchs of
Ireland); who married the daughter of the Duke of Acquitaine, and, on her father's death, became Prince and Sovereign of Acquitaine.” This principality continued in his
posterity until King Henry II. married Eleanora, daughter and heir to William, Duke of Acquitaine, and, about A.D. 1172, by his superior power, obtained Acquitaine; upon which event he brought over to England the two male descendants of **Lochan Delion**, viz.: **Sir Henry Delion** and **Thomas**, infants.

"The said Henry Delion (**now Dillon**), in 1185, was sent into Ireland, and King John granted to him there MacCarron's territory with part of Annaly and other vast possessions, to hold Per Baroniam in Capite, by the service of sixty Knight's fees. He was then honoured with Knighthood, and by this tenure (which was attended by a kind of sovereignty) he and his heirs were entitled to have summons to Parliament like the ancient Barons of England, who held their baronies by the same tenure.

"He built his mansion-house, with a Church, in Drumrany, also a Castle of Drumrany; and several abbeys (as those of Athlone, Holy Island, etc.), and other Churches and Castles. He was progenitor to all who bear the name of Dillon: a name of great note in the counties of Meath, Westmeath, Longford, Roscommon, Mayo, and other parts of Ireland, where, and in many foreign countries, they have flourished in the highest departments of Church and State."

(I'm afraid it would take all night if not forever for me to figure that one out, so I'll leave it at that for now.)

Alix de France, Comtesse de Vexin.

Alice of France, Countess of VEXIN, fairly closely related to Eleanor of Acquitaine (step-daughter, I guess).

Alice, Comtesse of Vexin is also a blood relative of Eleanor of Acquitaine (third cousin once removed).