King of the Rock
King of the Rock was the title used by the monarchs from House Lannister who ruled the western hills and valleys of Westeros that is now the westerlands. The capital of the Kingdom of the Rock was Casterly Rock near Lannisport.
The Lannisters trace their descent back to Lann the Clever, a trickster from the Age of Heroes who allegedly tricked the Casterlys out of Casterly Rock. There is no record of Lann calling himself king, although some have granted him the title posthumously. The first recorded King of the Rock was Loreon the Lion, who added the lands of House Reyne to his land and defeated House Banefort.
While King Tybolt Lannister defended the westerlands from the early Andal invasion, Kings Tyrion II and Gerold II allowed the Andals to marry into westermen nobility. An Andal knight, Joffrey Lydden, married into the Lannisters and, as King Joffrey Lannister, was the first Andal King of the Rock.
With Andal support, the Kings of the Rock expanded their realm. King Cerion conquered the land near the Golden Tooth, while King Tommen I added Fair Isle to the kingdom. Many Kings of the Rock, including Lancel I, Gerold the Great, and Lancel IV, warred with neighboring realms, including the Kingdom of the Reach, the ironborn kings of the Iron Islands, and the river kings of the Trident.
The last King of the Rock was Loren I, who bent the knee to Aegon the Conqueror after being defeated at the Field of Fire. While House Gardener was extinguished and replaced with House Tyrell during Aegon's Conquest, the Lannisters remained in control of the westerlands and became House Targaryen's Wardens of the West.
Known Kings of the Rock
- Lann the Clever, legendary founding ancestor of House Lannister during the Age of Heroes. Posthumously considered King of the Rock.
- King Loreon Lannister, "the Lion", the first true known Lannister king.
- King Tybolt Lannister, "the Thunderbolt", who made sure that the first Andal warlords in the westerlands met a bloody end.
- King Tyrion III Lannister, who instead of fighting the Andals, took their sons and daughters for wards and fosterlings.
- King Gerold II Lannister, son of King Tyrion III, who took the same approach as his father regarding the Andal invaders.
- King Gerold III Lannister, died without male issue. His only daughter's husband, Ser Joffrey Lydden, took the Lannister name and became the first Andal to rule the Rock.
- King Joffrey Lannister, married into the House, took his wife's name and was the first Andal to rule the Rock.
- King Cerion Lannister, extended his rule as far east as the Golden Tooth.
- King Tommen I Lannister, built a great fleet and brought Fair Isle into the realm.
- King Loreon II Lannister, held the first tourney ever seen in the westerlands.
- King Tywell II Lannister, who was identified by some as being the king in the tale of the Rat Cook.
- King Lancel I Lannister, "the Lion", rode to war against the Gardener kings and conquered the Reach as far south as Old Oak.
- King Loreon III Lannister, "the Limp", son of King Lancel I, lost all his father gained. 
- King Gerold Lannister, "the Great", sailed to the Iron Islands and returned with a hundred hostages.
- King Lancel IV Lannister, is said to have beheaded the ironborn king Harrald Halfdrowned and his heir with the House's Valyrian steel sword Brightroar in one swing. Invaded the Reach during the reign of Gyles III Gardener. He was killed by Ser Wilbert Osgrey at Red Lake.
- King Norwin Lannister, "the Niggardly", who was not known for his openhandedness.
- King Loreon IV Lannister, "the Lackwit", one of Casterly Rock's many weak, cruel and feeble kings.
- King Loreon V Lannister, known as "Queen Lorea", for he was fond of dressing in his wife's clothing walking the docks of Lannisport in the guise of a common whore. One of Casterly Rock's many weak, cruel and feeble kings.
- King Tyrion II Lannister, "the Tormentor", a strong king, famed for his prowess with a battle-axe, his true delight was torture.
- King Lancel V Lannister
- King Tommen II Lannister, "the Lion King", disappeared with the ancestral greatsword Brightroar during an expedition to Valyria.
- King Loren I Lannister, "the Last", last King of the Rock