House Casterly of Casterly Rock

Legend traces the family's origin to Corlos, son of Caster, a hunter from a village near where Lannisport now stands. Corlos killed the lion that had been plaguing his people but spared its cubs, and the gods rewarded that mercy by showing him a vast vein of gold.

That wealth let the Casterlys fortify the mine and dig ever deeper. Casterly Rock grew into the largest castle on the continent and its house into the richest in Westeros, though they never crowned themselves kings.

No army took the Rock from the Casterlys: Lann the Clever's wits did, and as many versions of that feat survive as there are storytellers to tell them. Some make him an adventurer from across the narrow sea; others, a man who found a hidden passage into the heart of the castle.

Once inside, he set the Casterlys against one another: whispering threats to sleepers, conjuring sounds that chilled the blood, moving treasures from one bedchamber to another so brothers accused each other, until the whole family believed the fortress haunted. Another tale has him driving vermin in through the secret way until the Rock emptied of its owners; in yet another he lets loose a pride of lions that devour the men, and Lann takes one of the surviving women to wife.

Some say Lann crept by night into the bedchambers of the house's maidens, and nine months later golden-haired children were born, while the girls swore they remained maidens still. Archmaester Perestan offers a version free of magic: Lann was no more than a man-at-arms in service to Casterly Rock who got the lord's daughter with child, and at the lord's death the lordship passed to her son by him.

Whichever path led there, the outcome was the same: House Casterly went extinct, and from Lann sprang the Lannister line, which has ruled the Rock ever since.