House Hoare of Orkmont was the last royal line to rule the Iron Islands before the Conquest, a black-haired, black-eyed kindred the maesters called the black line, or the black blood. The Hoares were old in the Age of Heroes: Harrag Hoare led the longships against King Theon Stark, and Erich the Eagle was reckoned a great king through the kingsmoot. Their crown of driftwood passed to House Greyiron in the days of the hereditary kings, but when the Andals came across the sea the Hoares allied with the invaders and with Houses Greyjoy, Orkwood, and Drumm to bring down King Rognar II, and Harras Stump-hand was raised up in his place to begin a new royal line that wedded the ironborn to Andal queens.
Through the long centuries that followed, Hoare kings veered between reaver and trader. Wulfgar the Widowmaker, Horgan Priestkiller, Fergon the Fierce, and Craghorn of the Red Smile waded in blood; the three Harmunds preferred coin and the Seven, and were despised for it by their own priests. Under Qhored the Cruel the realm of the ironborn touched its furthest reach, and it was said that every western shore where the salt of the Sunset Sea could be tasted lay beneath his fist. The Lannisters humbled the islands and razed Hoare Castle on Great Wyk in the time of Harmund the Handsome, but in a later age King Harwyn Hardhand carried the salt and the rock east, broke the Storm King Arrec Durrandon at Fairmarket, and seized the riverlands for the black line.
Harwyn's grandson, Harren the Black, raised Harrenhal upon the shores of the Gods Eye (the greatest castle in Westeros, and forty years in the building) to seat the Kings of the Isles and the Rivers far from the sea. The masons set the last stone on the day Aegon Targaryen landed at the mouth of the Blackwater. When the river lords forsook him and rode for the dragon, Harren shut himself within his walls and trusted to their thickness; Aegon brought Balerion overhead, and the Black Dread roasted Harren, his sons, and the whole of his line within the stone they had thought would shelter them. So ended House Hoare, and with it the last kingdom of the ironborn upon the green lands of Westeros.