Why did Ser Gregor kill Ser Hugh?

Question

During the Tournament in honour of Ned Starks appointment to Hand of the King (The Tourney of The Hand), Ser Gregor kills Ser Hugh of the Vale in what seems to be an accident.
However, both Ned Stark and Ser Gregor's brother - Sandor "The Hound" Clegane - seem to think that this was not an accident, and we are also lead to believe that it is not. Ned Stark seems to think that Ser Hugh was killed because Ned had wanted to question him.

However, in retrospect (ASOS), we know that it was not Cersei who killed Jon Arryn, we only know that she suspected that Jon Arryn and Stannis knew the secret of who really fathered her children.

I can imagine that Cersei would possibly have had Ser Hugh killed, just in case he actually knew something that she suspected Jon Arryn or Stannis might have suspected, but why would she do it at that time? And why use Ser Gregor in that case?

Looking back at it now, it seems that it is more likely that this was purely coincidental. If Cersei had suspected that Ser Hugh knew anything, she would have had him killed right away. And frankly, it could have been done at any time, and not at the tournament in front of half of King's Landing, done by her own father's bannerman.

What was the reason for Ser Gregor killing Ser Hugh?

Anything is possible, but I prefer having some evidence to support speculation. My personal opinion is that Ser Gregor would not take killing orders from just anyone. The man is not an idiot. It would have to be a Lannister, or someone like Pycelle who is a Lannister loyalist.

It seems that GRRM has left this particular event unexplained, when so many other events were actually explained. For example, we heard who sent the assassin to kill Bran, we have some clue as to what Ned promised Lyanna, we know who poisoned Jon Arryn and who gave the order, we know that Cersei tried to have all of Robert's bastards killed, etc. But no hint as to why this incident happened, besides the obvious?

Answer 1

It's just a Gregor thing

Here's what the author, George R.R. Martin has to say about this:

[Jon Nieve] At the end of A Storm of Swords we learned that Jon Arryn was poisoned by Lysa at the instigation of Littlefinger, but who ordered the death of Ser Hugh of the Vale? Cersei? Littlefinger?

[GRRM] It could very well have been either of the two, that's for you to decide. But, it could also just have been a Gregor thing. He's a murderous brute, and really needs no reason to kill someone.
^{-So Spake Martin http://www.westeros.org/Citadel/SSM/Entry/Asshai.com_Interview_in_Barcelona.}

In essence, it seems like this is something that isn't explicitly spelled out by The George. GRRM is notorious for leaving things to the readers' interpretation; but given that there isn't a 'story' behind this particular killing and since no-one has fessed up and taken responsibility, I attribute this to a coincidence; Gregor killed Ser Hugh, because well... Gregor!

Answer 2

This is pure speculation - and based on circumstantial evidence - but I suspect it was actually Littlefinger who was the orchestrator of Hugh's death. Firstly (and this is purely circumstantial), he adequately blocks Ned's first attempt to question Hugh. If you'll remember, when Ned announces his intentions to question Ser Hugh, it is Littlefinger who persuades him that he has to tread carefully. He advises Ned to send a trusted advisor to talk to Hugh, rather than go himself. Now, Littlefinger is an accomplished player of "the game" and I'm sure he would therefore have known all about the prickly disposition of Ser Hugh, and that he wouldn't answer the questions put to him by Jory (bit of a stretch here maybe, but I do think it extremely likely that Littlefinger would have known this).

Therefore it is my opinion that what initially appears to the reader to be helpful advice from Littlefinger (that Ned should question Ser Hugh but do so carefully) is now (in view of what we subsequently learn about him) revealed to be a skilful manipulation of someone unaccustomed to the game - and it is a great delaying tactic in terms of preventing Ned from actually learning anything from Ser Hugh. Now Littlefinger knows he has to resolve the situation before Ned can speak to Ser Hugh - and he has just enough time to set up the killing at the Tourney by Ser Gregor. Remember Clegane's status as an unpredictable wildcard here - given his nature it wouldn't have taken much convincing to get Ser Gregor to kill someone, so we needn't assume that he was acting to kill Ser Hugh on the orders of Cersei. Perhaps even the mere suggestion that the (unjustly) arrogant and jumped-up Ser Hugh should be cut down would be enough to get Ser Gregor to carry out the act.

So this leave Littlefinger's motivations as the loose end. Why does he need to do any of this? Well, we know that he wanted Arryn out of the way in order to marry his wife Lisa and later lay claim to the Vale. But we also know that, contrary to what he tells Lisa, Jon is not the only obstacle to his marrying her - what he needs is a title. At this moment he is still lowly Petyr Baelish of the Fingers. He won't become a viable suitor for her hand in marriage until he is nominated as Lord of Harrenhal, and for that to happen he is reliant on Cersei and her offspring maintaining their grip on the throne in the short term. What Arryn might have surmised about the Lannister children thus represented a severe threat to Littlefinger's plans - so perhaps Ser Hugh's killing wasn't necessary to protect Cersei and the Lannisters per se, but rather necessary to protect the Lannisters for the benefit of Littlefinger. A case of interests being aligned rather than the agency of one individual (Cersei) demanding the death of someone like Ser Hugh.

Answer 3

From their wiki page:

Sir Hugh

In a conversation with Eddard, Varys mentions Hugh as a possible suspect for poisoning Jon Arryn. Varys is pointing out that, although he owed everything to Lord Arryn, he did not return to the Vale when Lysa Arryn fled with her household there, instead remaining in King's Landing and rising to knighthood.

When Tyrion Lannister questions Grand Maester Pycelle about his role in the death of Jon Arryn, Pycelle denies it was him who poisoned the Hand, although he admits that he withheld care from him, as he knew that Queen Cersei wanted Jon Arryn dead. Pycelle believes Varys' version that it was Hugh who slipped the poison to Jon Arryn and supects that he acted on Cersei's orders

Hence his death at the hands of the Lannister bannerman is likely to be because Ned was trying to question him.

Answer 4

Any answer would be speculative but it is possible that

Littlefinger feared that Hugh knew something about his meetings with Lady Arryn and considered it the cheaper option to have Clegane kill him

Answer 5

If you have every tried jousting (or even just riding on horse and controlling a lance) it is very hard to do. It is unreliable to plan to kill somebody by means of a joust. Therefore while Gregor did end up killing a possible liability, I think the passage was just to show too often the dangerous and unglamorous part of the medieval tourney.

It also shows that Gregor Clegane isn't just some big brute but actually has technique and control

Sandor: Gregor's lance goes where he wants it to go.

Answer 6

If there was a plot, most likely Littlefinger, since Hugh's death makes Eddard suspect the Lannisters, which furthers LF's agenda for chaos and war. But there is a missing link between LF and Gregor, who does not take orders from the little man. So most likely an accident that plays into LF's hands.

Answer 7

GRRM leaves many (not all) questions like this unanswered because real life historical murder mysteries (unlike most fictional ones) often go unanswered (for ever) and his model is history, not murder mysteries. For a real life parallel to Ser Hugh's death, google King Henri II of France. The same thing happened to him on 10 July 1559 and the jury is still out.