Midway through Season 5, Episode 3 of Game of Thrones, Roose Bolton attempts to educate his newly-legitimized son Ramsay on how the Boltons rose to power: “we’ve become a Great House by entering into alliances with other houses and by parlaying those alliances into greater power. The best way to forge a lasting alliance isn’t by peeling a man’s face off, the best way is marriage.” And this theme of dynastic alliances both serves as the through-line of the episode and serves to ground it in medieval history.
The central difficulty of feudal politics – whether we’re talking about Europe after the partition of the Carolingian Empire in the 9th century and the rise of the modern nation-state in the 16th and 17th centuries, or Japanese history between the Genpei War in the 12th century and the end of the Sengoku Jidai – is that a system based on a liege lord distributing landed power to a military caste in return for their loyalty breaks down when fiefdoms become jealously-guarded inheritances instead of gifts that can be distributed and redistributed at will to keep vassals eager to gain favor and avoid wrath. Without this literal political capital, monarchs quickly became less powerful than their “overmighty vassals.”
One strategy that kings and queens turned to time and time again to buttress their authority (and lesser aristocrats to acquire even more and make a bid for royalty) was dynastic alliances between powerful families, secured through marriages. It’s a strategy that worked in medieval history all the time — whether we’re talking about the union of Henry II of England and Eleanor of Acquitaine that created a Angevin Empire, or the union of Isabella of Castille and Ferninand of Aragon that created the Kingdom of Spain, or the mighty Hapsburg Empire that was created more in the marriage bed than on the battlefield.
Fans of "Game of Thrones" are familiar with this strategy: after all, it was the marriage of House Stark to House Tully, House Tully to House Arryn, and the betrothal between House Stark and House Baratheon that formed the power bloc that brought down King Aerys the Mad, and the marriage between House Baratheon and House Lannister that kept the peace during the reign of King Robert. Indeed, House Lannister’s triumph in the War of Five Kings could not have happened without a fortuitous match between their House and the Tyrells and the breakdown of the Stark’s marriage alliance with the Freys. The principle is the same: if you can’t get loyalty by giving away land, you can grab power by marrying into land.
The problem, both in our own history and in Westeros, which the more you concentrate power, the more incentive there is for people to fight, and if necessary kill, to get their hands on it. Combine the lure of power and wealth with the sometimes fraught dynamics of families, and you get parents playing their children off against each other, siblings going to war over the succession, and mothers- and daughters-in-law jockeying for influence over kings. And the more that you bring great families together, the more cousins, uncles, nephews, and other relations there are to vie for power.
Alliances – can’t live with ‘em, can’t live without ‘em.
Our first example of the double-edged nature of alliances in this episode takes place in King’s Landing, as the Tyrell/Lannister union is simultaneously cemented through the wedding of King Tommen and Margaery Tyrell and brought into fresh tension by the rivalry between the Queen Consort and the Queen Mother. Just as Cersei finally has the Small Council the way she wants it, here comes Margaery, who effortlessly wins the love of the smallfolk and can manipulate the King in ways that she can’t. While the Queen Mother parries Margaery’s initial thrust – a suggestion to Tommen that mom might be happier in Casterly Rock, where she wouldn’t be able to treat the newly-deflowered king like a boy – it’s clear from Cersei’s reaction to the cheering of the crowd at the wedding and the mocking laughter of Margaery’s handmaids that she has the Tyrell Queen pegged as that prophesied “another, younger and more beautiful” who will take everything from her.
The problem that Cersei faces is that the Lannisters need the Tyrells – in the wake of the massacres that Robb Stark inflicted on the Lannister armies, they need Tyrell swords; with winter coming, they need Tyrell grain; with the Iron Bank pressing for repayment, they need financial support. But if Cersei can make Margaery no longer indispensable, then things might change.
And so Cersei reaches out to a new force in King’s Landing politics – the fundamentalist, evangelical movement within the Faith of the Seven known as “the sparrows.” Like the medieval Franciscans, the sparrows’ radical poverty and ministering to the poor brings them popularity among those same smallfolk who love Margaery. But unlike the Franciscans, the sparrows have no qualms with violence – if the High Septon is a corrupt sinner, he must be made to repent by any means necessary. Cersei offers a quid pro quo – if the Faith will support the Crown, the Crown will support the Faith, by putting the revolutionary at the very top of the religious hierarchy. And the High Sparrow might not like Margaery’s liberated sexuality any more than the closeted hypocrisy of the High Septon.
The problem is that the Queen has badly misjudged her new ally – the High Sparrow may be a self-deprecating sort, but underneath that he’s a religious revolutionary with deep historical roots in the smallfolk. If Cersei had paid better attention to her history courses, she should have remembered that when the pious start preaching that “we are equal in the eyes of the Seven,” that means more than soup kitchens. When the Targaryen monarchy was young, the Faith Militant rose up against the evil of incest and launched a guerilla war that nearly brought the Iron Throne crashing down. A hundred years later, a prophet calling himself the Shepherd roused the poor of King’s Landing to murder the dragons that had oppressed them, and the foundations of Targaryen power died in the Dragonpit along with thousands of burning martyrs. Only the Seven know what the High Sparrow will do, given the chance. And now Cersei has.
Meanwhile, two thousand miles away, another alliance is potentially forming out of Cersei’s sight. With Stannis perched on the Wall ready to march on Winterfell, Roose Bolton needs an alliance to give himself political legitimacy in the eyes of the North – and Petyr Baelish, Lord Protector of the Vale and Lord of Harrenhal, has the “perfect girl” to make that happen. For all her dramatic wardrobe change, Sansa is still a Stark of Winterfell, and that name “hath power to conjure with.” Whether it’s in the doomed resistance of Lord Cerwyn, whose flayed body hangs on the walls of Winterfell, or the quieter sentiments of the castle servants who whisper to Sansa that “the North remembers,” loyalty to the Starks runs deep in the North. With a marriage alliance to Sansa, Roose Bolton now has something even more powerful than armies – legitimacy – just as Stannis has lost his own potential Stark claimant to the Night’s Watch.
At the same time, in the careful fencing between Roose Bolton and Littlefinger, we can see the perils of dynastic alliances. To Roose’s face, Littlefinger claims that the Lannisters are a spent force, and dangles the possibility that an alliance between the North and the Vale could bring down King’s Landing as it did during Robert’s Rebellion. But before they arrive in Winterfell, Littlefinger suggests a hidden motivation to Sansa – that inside the castle walls, she can avenge her family against the family who betrayed the Starks. No fool himself, the new Warden of the North trusts Littlefinger not at all and insists on reading Littlefinger’s correspondence, to make sure that Baelish is only feigning loyalty to Queen Cersei.
For all that the Baelish-Bolton marriage alliance seemingly creates a new power bloc that could reshape politics in both the North and Westeros as a whole, the personal side of any marriage alliance could bring the whole thing crumbling to the ground. After all, we know how Ramsay treats women, and if the former Bastard of the Dreadfort should fail to restrain himself around Ned Stark’s daughter, the wrath of the Northmen would be impossible to control. And for Sansa’s part, that same loyalty to the Starks offers her a kind of power she hasn’t had in years: as far as the North knows, she is the rightful heir to Winterfell and the Boltons the men who murdered the Young Wolf. If she can tap into that, she might rule the North in her own right – and then the Boltons, and indeed Littlefinger himself, might have reason to be afraid.