No betrayal in the annals of the Seven Kingdoms is held blacker than the Red Wedding, for it was worked beneath the ancient protection of guest right, with bread and salt shared between host and guest. Its root lay in a broken oath. To win passage across the Green Fork at the war's beginning, King Robb Stark had pledged to wed a daughter of Lord Walder Frey of the Crossing; but at the Crag he gave his heart and hand instead to Jeyne Westerling, and so shamed the proud and prickly old lord. To mend the breach, Robb agreed that his uncle Ser Edmure Tully would wed a Frey maid in his stead, and the whole northern and river host turned aside to the Twins to see the marriage done as they marched home to relieve the north.
What Robb did not know was that Lord Walder had already made his peace with the Iron Throne, conspiring with Lord Tywin Lannister and, blackest of all, with Robb's own bannerman Roose Bolton, who had wed a Frey bride of his own and sought the north for himself. The wedding feast at the Twins was rich with food and music, and the guest right honored in show; but when the bedding was done and the doors were barred, the musicians set down their instruments and took up crossbows, and the song called The Rains of Castamere gave the signal for slaughter. Queen Catelyn saw the hidden mail beneath Lord Roose's sleeve too late. In the hall and in the camps beyond, Frey and Bolton men fell upon the northmen while they were drunk and unarmed.
King Robb was riddled with quarrels and then, some say, finished by Roose Bolton's own dagger with the words that Jaime Lannister sent his regards; his direwolf Grey Wind was slaughtered in his cage, and his corpse was defiled, the wolf's head sewn upon his shoulders in mockery. Lady Catelyn, having taken a Frey hostage and seen him butchered before her eyes for naught, was cut down with her throat opened, her body cast into the Green Fork. The Stark host was destroyed, its captains slain or taken, and the young wolf's cause died with him in the rushes of that hall. The north would remember, and the rivers would not soon forgive; but on that night House Frey and House Bolton had their price, and the Iron Throne was avenged upon the King in the North.