House Clegane of Clegane's Keep is a knightly house of the Westerlands, sworn to Casterly Rock. The line is of recent making: the grandfather of Ser Gregor Clegane was kennelmaster to the Lannisters, a man of low birth who kept the dogs of the Rock. When a lion escaped its cage and set upon Lord Lannister, the old kennelmaster loosed his hounds to drive it off, losing an eye in the struggle but saving his lord's life. As reward, the lord granted him a small patch of land, raised him to knighthood, and let him keep his dogs. The kennelmaster's grandson blazons those three hounds on gold, a coat of arms that tells the whole of the family's rise at a glance.
No words have ever been attributed to the house in any record the maesters keep, which suits a line that has never traded in words. By the time A Game of Thrones opens, the house has shed its second generation: the father of Gregor and Sandor Clegane died under circumstances the smallfolk whisper about, leaving Ser Gregor, called the Mountain That Rides, as lord in name and deed. The elder brother serves as Tywin Lannister's most feared enforcer, a seven-and-a-half-foot instrument of terror whose deeds in the Sack of King's Landing and in Tywin's wars have made the three black dogs as much a symbol of dread as of loyalty. His younger brother Sandor, the Hound, keeps no lordship of his own and seeks none, serving instead as sworn shield to Prince Joffrey at King's Landing.