The Kings of the Reach (House Gardener)
The green hand of Garth Greenhand, ruling the richest and most populous country in Westeros ÔÇö until every last one of them died in a single afternoon.
The fuller tale
Garth Greenhand is the ancestor half the Reach claims: a First Men king said to have brought farming to Westeros, and to have fathered so many children that the Tyrells, Hightowers, Florents, Rowans, Oakhearts and a dozen others all descend from him if you ask them. His line, House Gardener, ruled from Highgarden for thousands of years and made the Reach the wealthiest region on the continent ÔÇö more men, more grain and more chivalry than anywhere else, and a chip on its shoulder about Oldtown.
King Mern IX brought the largest army the Conquest ever faced to the Field of Fire, together with his sons, his grandsons and his nephews. All three dragons flew that day, and House Gardener ended in the space of a few hours ÔÇö the only great house of the Seven Kingdoms to be extinguished root and branch.
Their steward knelt, and was given Highgarden for it. Which is why, three hundred years later, the rose flies over the Reach and half the Reach still remembers that the Tyrells were upjumped stewards.
The ground they held
 See the world in 2 BC on the timeline What became of it  if an ending is written, it is here. Spoilers.
The chronicle records no ending here ÔÇö or none the maesters have set down.