House Tyrell is the principal noble house in the Reach; many lesser houses are sworn to them. Their seat is at Highgarden, a castle near the Manderly river. Their sigil is a golden rose on a green field, and their words are "Growing Strong."

The Tyrells trace a line of descent, through the female line, to the legendary Garth Greenhand, the first King of the Reach in the Age of Heroes. The Tyrells were stewards to House Gardener, the ancient ruling line of Kings of the Reach, who periodically intermarried with lower ranking houses of the Reach such as Tyrell or Florent. After House Gardner was extinguished in the War of Conquest, the Tyrells surrendered Highgarden to the Targaryens. For their service they were created lords paramount in the Reach and Wardens of the South.

ALLIED HOUSES: Baratheon
ENEMY HOUSES: Lannister