Red wedding and Red viper

[leonardof]

Guest right means the host can't kill a guest. Oberyn was not host to Tywin.

[Praetor Xyn]

The biggest clue to Oberyn poisoning Tywin was Pycelle rambling off a list of poisons but the only one he gives a description of is Widow's Blood, which basically shuts down the bladder and bowels until a person dies from their body's own poisons.

We know that Tywin was on the privy for a very long time since Shae had fallen asleep in his bed, which doesn't happen in 15 minutes generally which is a generous overestimate for using the privy.

Couple this with the horrid stench at his funeral which it was made abundantly clear isn't normal even by Westerosi standards, and it's very plausible, I'd argue there is way more evidence for it than R+L=J which is basically taken as fact.

On topic guest right protects the guest from the host, not the other way around. So it was impossible for Oberyn to break it unless Tywin visited him in Dorne.

[Lady Blizzardborn]

13 hours ago, Maxxine said:

I think this is the important part for the OP and the most unclear part. Was Oberyn a guest thus invoking guest right and, if so, would Tywin be protected by that guest right? Even though he was there under small council I would argue he was still a guest and protected by guest right because of the invitation. For instance, even though Myrcella technically lives in Dorne now I think she is still protected by guest right. I don't know if everyone who lives in a location is protected by guest right though or or just the lord or just the family. I would think it would at least be the family of the lord so Tywin would be protected.

I don't think the OP is comparing "apples to wildebeests" when it  comes to guest rights. From what we know in the story the reason for breaking guest right doesn't matter to the gods. Justified or not, breaking guest rights means being cursed. I think the OP makes a good point that we as readers gloss over Oberyn (assuming he did have guest right) because we like him more and he had was more justified in what he did (assuming he killed Tywin).

Guest right applies to guests. People working somewhere are not guests. Guests are temporary visitors, and usually (though not always) there for social reasons. Oberyn's place on the small council means he's there for work, not a pleasant visit. Had he not been killed in the TBC, Oberyn more than likely would have stayed on in KL and become a semi-permanent resident. Hence not a guest.

And poisoning doesn't necessarily equate to killing. It is possible to poison someone just enough to make them sick.

Whether making someone sick temporarily counts as violating guest right is a matter for discussion but we're not likely to be able to easily decide the question. It reminds me of a scene in Firefly when Shepherd Book wants to help the crew fight some bad guys and the Captain asks him doesn't his Bible have some rather strong words to say about killing. Book replies with something along the lines of "Yes, but it's rather fuzzy on the subject of kneecaps."

[Leo of House Cartel]

While we can't be sure on The Laws of Hospitality, until we get a better description from someone like Bloodraven or a COTF, do they only apply to someone doing harm to the ruler of the area they are guesting? 

If so, then would The Red Keep count as Tywins house? I doubt it, his would be Casterly Rock. Wouldn't it have technically been The King giving Oberyn bread and salt at the speculated time of Tywins poisoning? So one could perhaps view Tommen/Joffrey as the ones guesting the Viper, meaning he might have no godly repurcussions to deal with if he poisoned fellow "guest of The King" Tywin. Oberyn did come to King's Landing to serve under the small council, and would surely be viewed as a guest of the King, on paper anyhow.

[Maxxine]

9 hours ago, Lady Blizzardborn said:

Guest right applies to guests. People working somewhere are not guests. Guests are temporary visitors, and usually (though not always) there for social reasons. Oberyn's place on the small council means he's there for work, not a pleasant visit. Had he not been killed in the TBC, Oberyn more than likely would have stayed on in KL and become a semi-permanent resident. Hence not a guest.

And poisoning doesn't necessarily equate to killing. It is possible to poison someone just enough to make them sick.

Whether making someone sick temporarily counts as violating guest right is a matter for discussion but we're not likely to be able to easily decide the question. It reminds me of a scene in Firefly when Shepherd Book wants to help the crew fight some bad guys and the Captain asks him doesn't his Bible have some rather strong words to say about killing. Book replies with something along the lines of "Yes, but it's rather fuzzy on the subject of kneecaps."

You make good points concerning being a resident. I'm just not so sure it's that black and white.Regardless of him working in KL, that's still not his home so I feel l he's still should've protected by some "rule" (that also would've protected Tywin from him). Maybe it's something less than guest right. I'm sure he was promised safe conduct or something, so maybe Oberyn potentially Tywin was just the garden varierty betrayal.

I'm pretty sure guest right covers all harm, not just killing someone. So poisoning would still violate it. Also I think whatever the poison it was meant to kill Tywin, not just be temporary. Idk if anyone has every said this or if it can be confirmed but I'm thinking the poison was whatever Tyrion gave Cersei in Clash but in a much higher dose.

[Lady Blizzardborn]

20 hours ago, Maxxine said:

You make good points concerning being a resident. I'm just not so sure it's that black and white.Regardless of him working in KL, that's still not his home so I feel l he's still should've protected by some "rule" (that also would've protected Tywin from him). Maybe it's something less than guest right. I'm sure he was promised safe conduct or something, so maybe Oberyn potentially Tywin was just the garden varierty betrayal.

I'm pretty sure guest right covers all harm, not just killing someone. So poisoning would still violate it. Also I think whatever the poison it was meant to kill Tywin, not just be temporary. Idk if anyone has every said this or if it can be confirmed but I'm thinking the poison was whatever Tyrion gave Cersei in Clash but in a much higher dose.

I don't really see it as a betrayal, but that may be because of my stubborn adherence to the possibility that guest right wasn't in effect. Even without getting into the residence/work aspect, if Oberyn was eating anyone's bread and salt, it was Joffrey's, not Tywin's. And we all know that the bread at least actually came from the Tyrells. 

I agree that the one Tyrion gave Cersei is a good possibility. And it plays in to Tyrion knowing he'd find Tywin in the privy if Tyrion also knew Oberyn slipped something into Tywin's wine or food.

But since we still don't have any proof of the poisoning, it's all just incredibly fun conjecture.

Speaking of which, and emphasizing the incredibly fun part, going back to the rather cracked pot of the Martell-Tyrell feud being a front, and adding in that Oberyn's having been a known poisoner would mean people would be watching him carefully, maybe Mace slipped Tywin the poison. I can't help thinking of an Agatha Christie story where the line "there was another person at that table" comes up. No one would have expected Lord Tyrell of anything like that, which makes him the perfect one to do it. Since we're talking about a non-provable poisoning anyway...

And that lessens the likelihood that it was meant to be fatal, as Mace had no reason to want Tywin dead unless he wanted Tywin's job and there's no reason to think that unless Mace is less of a dolt than he allows people to think. It also kind of fits with Olenna being involved in Joffrey's death. Why not two poisoners in the same family? It's almost like a bonding thing--Oberyn and Tyene, Olenna and Mace. Isn't it wonderful when families maintain common interests?

[Shouldve Taken The Black]

This theory makes some sense to me (although I agree that when repeating a theory others have already developed, an OP needs to offer more evidence or insights rather than just trot out the assertion once again without qualification). However, what I get stuck on with this idea, is how will it possibly come out, now both Oberyn and Tywin are dead? Oberyn may have shared his plans with others, but the most likely people to for Oberyn to confide in are the Sand Snakes and Dameon Sand, and none of them have shown any indication that they knew anything about it.

[JonCon's Red Beard]

There is no way Oberyn didn't do it, but I have the feeling we're never going to find out he did until the books are finished and someone goes and ask GRRM himself bc the book won't tell us.

I mean, Oberyn really really REALLY hated Tywin. He blamed him for everything that happened and wanted him dead and destroyed, I think Oberyn wanted first to make the mountain confess and accuse Tywin in front of everybody to humiliate him and later, to get him killed.