It may simply be a reedition of IOTL problems for macro-historical matters, except this time without Aquitaine (unless Alienor dies quickly, then the matter would becomes suddenly more complicated) which, depending on who Alienor goes with, may play an interesting if different role.
That said, Geoffroy doesn't seems to have been as much skilled or maybe simply as ambitious as his brother, being more focused on regional matters : if it's too change due to his station or not is anybody's guess.
If continental disputes may be more about north-western part of the Kingdom of the French, rather than in Aquitaine, it could admittedly lead to a possible Capetian/Blois alliance, similar to the Capetian/Raimondin historical one.
(Which incidentally, may mean a lesser royal presence south of Loire in the mid-XIIth century).
It could change, however, depending on who Alienor (if she survives) marries (or not).
In France, the more likely possiblity IMO would be Thibault V of Blois, that IOTL tried to marry her after the dissolution of her union with Louis VII or Henri I of Champagne. It would certainly make Blois/Champagne and Aquitaine a main target of Capetian policy, without them having nearly as close the same force than IOTL Plantagenêt.
There, I'd see then a similar course than IOTL between Raimondins and Capetians as IOTL for the mid and late XIIth century, in spite of a more "truel" situation between Plantagenêts/Capetians/Blois
(Capetians probably turning back to the old good geopolitics of switching sides to preserve most of balance and slowly obtain gains).
Guigues V of Dauphiné, or Raimon-Berengier II/III of Provence may be good prospects, would it be only to open a second front against Raimond V, but it would ask for the latter to end the Baussenques Wars, and both weren't nearly as prestigious than Henri Plantagenêt or Thibault de Blois.
After that, similar problems would arise : how to rule efficiently both England and a patchwork of divided principalities under Capetian suzerainty.
However, if he dies as IOTL without posterity, expect Anarchy II : electric bugaloo
It would be extremely frowned upon, as contrary to canonic law : two in-laws can't re-marry with each other, safe a big dispense (under the argumentation of non-consumnation?) that I don't think would be pulled, it's just too close there.
Obviously, Geoffrey is very much a bit player in history, so it's difficult to say anything that isn't related to who Alienor marries afterwards. However, it's possible that the people of England would be a bit disappointed by how short the reign of Henry II lasted, and may not be very pleased with Geoffrey. So if Alienor does marry Thibaut de Champagne, it might be quite interesting to see an attempt to restore the House of Blois in England in the 1150s or 1160s. Who wins this is up in the air, but I'd presume that England was so sick of violence at this point that they'd just fight for the status quo under Geoffrey and tell the invaders to get lost.
Interesting, do you not think that Eleanor would want to marry Geoffrey then?
As LSCatilina says, it was against canon law. That said, marrying Henry was against canon law as well, but marrying a (IIRC) second or third cousin was a lot more acceptable than a brother-in-law.
However, if we're talking about Henry dying before he marries Alienor, then everything changes:
- Eustace of Blois' death will be butterflied, so Stephen will be more reluctant to deal with the rival dynasty
- Geoffrey is now the claimant to the Kingdom of England. If he loses, Stephen's family will stay on the throne indefinitely.
- The most likely husbands for Alienor will be Geoffrey or Thibaut. If the former, he has a better chance of winning against Stephen and Eustace, if the latter, then what LSCatilina said still applies.
So, he dies in 1151, before the end of Anarchy?Okay cool, and if say Henry II dies before he can marry Eleanor?
However, it's possible that the people of England would be a bit disappointed by how short the reign of Henry II lasted, and may not be very pleased with Geoffrey.
So, he dies in 1151, before the end of Anarchy?
Eustace of Boulogne, son of Stephen, is still pretty much alive and there's nothing preventing him to outlive his father and have a longer life.
Does it means that the Anarchy is going to last on and on, between Blois and Anjou?
I don't think it will : both sides were simply tired of war and of the whole chaotic situation, nobody being really able to takeover their rivals. Eustace may want to take all of what he sees as his own, but more he would tries, more he would encounter resistence from his own ranks.
On the other hand, both Geoffrey and William may not be as interested on continuing the war, being more focused on their continental interests.
Eventually, I think you'd see the separation of Norman inheritence between Eustace (England) and Geoffrey (Nantes, Anjou) with Normandy being debatable but at this point I think it would goes to whoevers controls it, aka Angevines.
It doesn't mean that you won't have ulterior wars (or even wars with Blois/Champagne) for at least control on Normandy, but I don't think it would be an immediate outcome.
The situation would change Capetian politics, as they could benefit from a division among these great princes, and assert a policy of balance at worst.
They wouldn't be able to play on the huge divisions of Plantagenet hegemony as IOTL (meaning favouring civil wars among them), obviously, but they are also less pushed back allowing a more gradual expansion towards Lower Loire and Lower Seine (which incidentally, would force them to ally with one, only to switch alliance at another moment)
At this point tough, I think people in England and especially nobility would be tired of the Anarchy and especially to fight each others : something akin to "class solidarity" among nobility played more than once to prevent too much important civil wars, especially if there's nothing to win.
You can see that, during 1153's campaign, no side had particularily enthusiast forces.
Geoffrey represents a possibility of a smooth succession (at least for what matter Angevine and English customs), and that's would weight a lot onto contemporary mentalities.
That's going to be hard, giving she divorced with Louis VII in 1152.If Geoffrey does marry Eleanor, before his brother can-meaning Henry II does die in 1151. Then that in itself raises more potential butterflies.
And Eustace would still want Normandy. But what they want at this point doesn't matter : both sides are weary and not really willing to continue the fight without clear perspective on one side's clear victory.though a part of me does think Geoffrey would still want England.
That's going to be hard, giving she divorced with Louis VII in 1152.
One could argue that the abduction that Geoffrey attempted in 1152 could workd, tough. It could so backfire, on the other hand, even if he pulls a marriage at gunpoint. Namely, she would probably ask Thibault of Blois to marry her, as he was more powerful than Geoffroy and able to deal with such situations.
Basically? You have good chances having Thibault of Blois attacking Geoffrey, for hisd own interests, which would grealty help his brother.
And Eustace would still want Normandy. But what they want at this point doesn't matter : both sides are weary and not really willing to continue the fight without clear perspective on one side's clear victory.
Well, the loss of Normandy would probably mean that Anglo-Normans lords that held titles on both sides of the sea would certainly be deprived of it, which may become one of the causes of an ulterior war, indeed.