For forty years Harren the Black, called Harren Hoare, King of the Isles and the Rivers, had labored to raise the mightiest castle in all Westeros upon the shore of the Gods Eye. Five towers of black stone he built, each taller than any that had gone before, and he beggared the riverlands and worked untold thousands of captives to death in the raising of it, so that men said the very mortar was mixed with blood. In the same year that the last stone was set, Aegon the Dragon came into the riverlands. Harren, secure behind walls so thick and high that no army could hope to storm them, shut himself up in Harrenhal with his sons and his host and made ready to withstand a siege, boasting that no man could take his seat.
But Aegon had not come with an army to camp before the gates. He waited only until the dark of night, then mounted Balerion the Black Dread and flew above the castle, and from the sky he loosed the dragon's fire upon it. Stone does not burn, as Harren had reckoned, but the men within it do, and so do timber and cloth and bedding and all the living things that a castle holds. The towers became as great candles in the night; the iron of the portcullises glowed cherry-red and the very stones cracked and slumped in the heat. Harren the Black and all his sons died that night within the tallest of the towers, ever after called the Kingspyre, and with them ended the line of the ironborn kings who had ruled the riverlands with a heavy and hated hand.
The riverlords had little love for the man who had ground them beneath his heel, and many had already thrown off his yoke; Lord Edmyn Tully of Riverrun had declared for the dragon before ever Harren burned. When the deed was done, the lords of the Trident came before Aegon and bent the knee, and he named Edmyn Tully Lord Paramount of the Trident and overlord of the riverlands in reward for his loyalty. Harrenhal itself, blackened and half-ruined, passed to a succession of houses who found little joy in it, for men have whispered ever since that the great castle is cursed, and no line that has held it has long endured.