Being Gregor Clegane was a landowner of the Clegane house at the service of the Lannister house, Sandor Clegane's older brother. Due to its large size, it is known as the mountain that rides, or simply the mountain. Gregor Clegane was the eldest son of the head of the Clegane house, who, in turn, had been the son of the founder of the house, a c...Read more