Game of Thrones, based on the Saga of Fire and Ice books, and Final Fantasy Tactics are two important parts of modern Nerdy Pop Culture (one is currently a bit more obscure then the other) that have in common drawing inspiration from the chapter of English history known as the War of the Roses. But with some clear major liberties.
Both are also very dark pessimistic and arguably deconstructive takes on the High Fantasy Genre, I guess the War of the Roses isn't the most ideal piece of history to draw on if you wanna be Optimistic.
Both Ivalice and Westeros were originally Seven Kingdoms, just like England which was seven Anglo-Saxon Kingdoms united by Ælfrēd The Great. Aegon Targaryen being a conquer from outside Westeros however would make a closer analogy to William The Conqueror then Ælfrēd.
One thing I wonder if anyone else has noticed is that when you apply how Westeros' geography equates to England's, The Wall that is such a big plot point is clearly inspired by Hadrian's Wall.
The scenario also involves an "Evil" Queen who's son may or may not be the son of her Kingly husband. But how exactly she relates to the House that sides with her tends to be changed.
And both are a conflict between North and South. Perhaps the least unique of the defining characteristics. There was a North v South civil war in the history of my country also. Bible scholars know that happens in the Bible twice (with Israel and with the division of Alexander's Empire in Daniel 11). And it's part of Ancient Egypt's history. And since we'll be talking some Japanese media here there was also a time when Japan was divided between rival branches of the Imperial Family, one based up North and the other down South.
There are some key differences in how the two draw inspiration from it.
The most superficial thing is the way Tactics geographically switches the scenario somewhat. In both the History and GoT it's the Southern House that sides with the Queen, while in Tactics it's the North.
But the biggest distinction is that Martin was largely drawing on the popular perception of the war that viewed the Yorks as the good guys, at least before the Yorks internal conflicts messed everything up. Richard 3rd Duke of York was largely the basis for Ned Stark, and Edward IV the basis for Robb Stark.
But in Tactics both Dukes are equally selfish pricks who care nothing for the suffering their war brings on the common people they're supposed to be responsible for. And they're not even the most Evil characters in the story.
Both also have a lot in common in how they change the story interestingly.
In the real War of the Roses both houses were branches of the Royal Family. Siding with Lancaster was by traditional standards siding with the rightful heir, the Duchy of Lancaster was created specifically to be the King's Duchy. While the Dukes of York descended from a different son of one of the earlier Plantagenets. The Duke of York held a relation to the Royal family comparable to the Duke of Orleans prior to the French Revolution.
But in both GoT and Tactics the warring houses are separate Noble Houses, and the Royal family effectively going extinct is partly what causes the conflict. In both the Queen is a member of one of the rival houses who married the King. While historically the Queen was a foreign (French) royal who married the King of England, who was a Lancaster.
All three have in common a suspicion (though in Tactics it is very vaguely hinted at while in GoT it's blatantly confirmed) that the actual father of the Queen's son is a member of the House that sides with her. But because of the above change this makes both fictional scenarios Incestuous, while historically it would not have been (I won't venture to guess if it's true or not).
As Fantasy stories it's not surprising both add supernatural elements. It's interesting how they both bring them in in a similar way. An inhuman menace threatens to destroy the world and the internal selfish squabbling of the people who run it have them totally uninterested in dealing with that. Like they're taking Reagan's whole "if Aliens attacked we'd all come together" slogan and saying, "no we wouldn't".
That's not necessarily the only way to bring Cosmic Horrors into it. You could go further then Martin in siding with the North by having the Demons side with Lancaster and the Angels side with York. But that would lack nuance I suppose. In Homer's depiction of the Trojan War the gods all took sides in the conflict, I would probably emulate that.
Both are likely to be very different from history in how they end. Martin's isn't over yet so we don't know for sure. But it seems like there is hope that maybe eventually they will come together and deal with the real threat. But as a Video Game FF Tactics has to be a story where the character you play and the party he forms save the world mostly on their own, the depressing part is in Universe no one knows what Ramza did and the biggest @##hole is remembered as a hero.
If whoever rules when the dust settles isn't exactly either side fighting each other when it all started. Then that "winner" could be viewed as allegorically Henry VII to some extent. In tactics this would be Delita Herial (and maybe Ovelia would be Elizabeth of York?). But an important plot point of the game is that Delita was a complete commoner. Henry Tudor had a distant connection to the Lancaster line, but more importantly he was a direct heir to the Princes of Wales and thus to the Kings of the Britons who ruled the Island before the Anglo-Saxons came. Because of this he was heralded as the Mab Darodan and the return of King Arthur.
Who would make the most sense in that context in Game of Thrones? Maybe a Targaryen since Pendragon means head of the Dragon. And Henry Tudor was a direct descendant of Maelgwn who Gildas called "The Dragon of the Island". Arthur means Bear but none of the houses of Westeros have a Bear as their symbol. Henry Tudor invaded crossing the channel from France, which could fit what Daenerys is planning to do.
Also GoT doesn't have an allegorical vilification of Christianity. It has religious themes, but not so blatantly anti-religious.
They are no doubt not the only works of fiction to drawn inspiration from the War of the Roses. Though I'm hardly an expert on the subject. But I know that the first such example would actually be Le Morte d'Arthur, which has to a large extent defined Arthurian legend ever since. Thomas Mallory was actually contemporary with the War of the Roses, so for his time the influence of that War on fiction was more like WWII and Vietnam are for us. The actual geopolitical scenario in the story makes far less of a direct analogy, the parallels that do exist are ones you may have to be a contemporary to get.
There has also been fiction that directly depicts the history involved. Starting with Shakespear's Tetrology, (the Henry VI trilogy and Richard III). I rather enjoyed The White Queen TV Series, haven't read the books.