To provoke House Tully to war upon ground of his own choosing, and to answer the seizing of his son Tyrion upon the kingsroad, Lord Tywin Lannister loosed his cruelest captains upon the smallfolk of the riverlands. Foremost among them rode Ser Gregor Clegane, the Mountain That Rides, whose riders crossed out of the westerlands and put the villages of the Red Fork to fire and sword. They burned the Mummer's Ford, Sherrer, and Wendish Town, slaughtering the men, ravishing the women, and driving off the herds, and they did it under no banner, that the crime might not be laid plainly at Casterly Rock's door.
Word of the burnings reached King's Landing while Lord Eddard Stark sat as Hand of the King. In the king's name Lord Eddard sent out a party of a hundred and twenty men under Lord Beric Dondarrion of Blackhaven, with the red priest Thoros of Myr among them, charged to bring Ser Gregor to the king's justice and to answer for the ravaged smallfolk. But Ser Gregor and his men were waiting. At the Mummer's Ford they fell upon Lord Beric's company and cut it to pieces, scattering the survivors into the woods. Lord Beric himself was gravely wounded and left for dead, yet he did not die; from the broken remnant of that party would rise the Brotherhood Without Banners, who would harry Lannister raiders in the riverlands for years to come.