Catelyn's brother Edmure Tully places Catelyn under house arrest at Riverrun, but Robb pardons her after he announces his wedding to Jeyne Westerling, invalidating his marriage proposal to House Frey. Lord Walder Frey agrees to forgive Robb if Edmure marries his daughter Roslin, and Catelyn travels to the Frey seat of the Twins to attend the wedding with Robb and other northern lords. However, Walder Frey and his men take revenge on Robb for his slight on their house by slaughtering the northern host, an act of treachery that became known as the "Red Wedding". In an attempt to save her son's life, Catelyn takes Aegon Frey hostage and kills him when Roose Bolton kills Robb regardless, but she still has her throat slashed by Raymund Frey. The Freys then mutilate Robb's corpse, and throw Catelyn's stripped naked corpse into the Green Fork in mockery of House Tully's tradition of river burial.