Highgarden

A castle of white towers and climbing roses above the Mander, seat of Lord Leo Tyrell, called Longthorn — Warden of the South and liege lord of half the tale's small houses.

The fuller tale

Highgarden is the Reach entire, distilled into one castle of white towers wound about with climbing roses — the seat Aegon the Conqueror granted to the Tyrells, stewards rather than blood of the fallen Gardener kings, in the settlement that still rankles houses with a better claim by birth and a worse one by loyalty. In Dunk and Egg’s age it belongs to Lord Leo Tyrell, called Longthorn, Warden of the South, and liege lord in one form or another to nearly every Reach house the tales touch — Ashford, Standfast, Coldmoat, Cider Hall, Starpike, Goldengrove, all of them ultimately answerable, however distantly, to Highgarden’s word.

That authority mostly stays offstage in the novellas, which is itself the point: a well-run overlordship is one that never has to be invoked, and the water war between Standfast and Coldmoat resolves itself in the marches without ever troubling Highgarden’s court. The Reach’s great and small houses squabble, marry, and occasionally bleed within a peace that Highgarden guarantees simply by existing at the top of it — the quiet, unglamorous kind of power that outlasts every tourney champion the era produces.

In the first season

Lord Leo Longthorn does not trouble himself with Lord Ashford's tourney — but every knight on the meadow knows the rose of Highgarden outranks the field.

The fallen of this place — if any, they are named here. Spoilers.

No death the chronicle records has come to this ground — or none the maesters have set down.