CK2: Wars of the Usurpers: How to take the Iron Throne

"Tell me, what right did my brother Robert ever have to the Iron Throne? Oh, there was talk of the blood ties between Baratheon and Targaryen, of weddings a hundred years past, of second sons and elder daughters. No one but the maesters care about any of it. Robert won the throne with his warhammer."

-Renly Baratheon to Catelyn Tully

A few posts ago, we talked about defending the Iron Throne as the Targaryens. Now we're going to talk about taking it from them.

And unfortunately, as far as CK2 goes, Renly is wrong. You need a blood tie to justify your claim to the Iron Throne.

This is where Vanilla CK2 players may get worried: the game states the Iron Throne's succession law to be agnatic, meaning (in the strict sense of the word) that only men may hold the throne, and the line may not pass through a woman.*

This is where the mod diverges from vanilla, though. The Iron Throne in the Game of Thrones mod uses Targaryen succession law, which is a modified form of agnatic primogeniture. In Targaryen succession, the line can pass through a woman, but only after all possible males have been exhausted. The game models this by giving all Targaryens (and Blackfyres) claims to the Iron Throne by virtue of being the blood of Old Valyria. If I remember correctly, men get Strong Claims, women get Weak Claims (with the exception of Daenerys Targaryen, who gets a Strong Claim). And you can push a woman's claim to the throne, which is not possible under agnatic primogeniture in vanilla.

Most of these claims go unnoticed, and fade away. But a usurper can push his wife's claim to the Iron Throne, and then the throne will pass to his son.

Here's where things get nasty. The game's "megawar" system means that no two wars will be the same, and every lord has a chance to decide the side he will come down on. And you need to win not just one war against the Targaryens, but probably 2: the first war to depose your king and have him replaced by his child heir (and thus allow weak claimants to contest the Iron Throne), the second to supplant the child with your wife. Or you could wait for a another male Targaryen, or perhaps a Blackfyre, to start a war for the Iron Throne, which will then allow you to push your own claim. Or you could assassinate the king.

Be very careful about deposing the king, which lowers crown authority by one step. If you somehow get stuck in Autonomous Vassals, you aren't getting out of it, it's damn near impossible to change crown laws in Westeros.

Now let's talk about the megawars. You'll want the Reach on your side. I find that if you control 1.5-2 regions, having the Reach on your side will give you a good chance. Have the Reach at +100 opinion and a marriage tie to them (not hard if you park your Master of Laws in Highgarden). If you wait for a new ruler to take the Iron Throne, and start a war immediately, the Reach will almost always side with you. Barring that, try to have the Westerlands and some random high lords on your side. 

It will take some doing to usurp the Iron Throne, but don't you think it should be hard to become the King?

Started as Hoster Tully in 259 AC, my kid took some land, allied with the Reach, and married Aerys II's daughter. Rhaegar died of an illness, and so after Aerys II died the throne went to his kid. I pushed the wife against the kid and took the throne.

*Historically-minded readers may recognize that the English, in the Hundred Years War, claimed that Edward III had a right to the French throne by virtue of being the closest living relative of the dead Charles IV. However, the French claimed that under agnatic primogeniture ( a tenet of Salian law), the line of succession could not pass through a woman, so they crowned Philip VI of Valois.