House Tarth of Evenfall Hall rules the Sapphire Isle, a high green country northeast of Shipbreaker Bay whose cliffs stand sentinel over the Straits of Tarth. The family's blazon is a curious quartering — suns of gold upon a rose-coloured field beside white crescent moons upon azure — and the heads of the line bear the name Evenstar, a title they claim has descended from the dawn of days. No words of House Tarth are recorded in any maester's chronicle.
The ancestors of the Tarths were kings in their own right before the coming of the Andals, the last of whom, Edwyn Evenstar, gave his daughter in marriage to Durran the Fair of House Durrandon and so brought Tarth under the dominion of the Storm Kings. When the Andals came across the narrow sea, Tarth was the first of the storm coasts to fall, and the blood of the conquerors and the First Men ran together in the house thereafter. The Evenstars of Tarth bent the knee in turn to House Baratheon after the Conquest and have served the lords of Storm's End loyally through the centuries, supplying ships in the Daughters' War and answering the call of the Iron Throne when Myrish exiles assailed the isle in 92 AC.
At the opening of A Game of Thrones the lord of Evenfall is Selwyn Tarth, the Evenstar, an aging widower who has buried a wife, a son, and two infant daughters. Only Brienne remains to him — tall, plain-faced, and stubborn of arm — and she is heir to Tarth in her own right. When the War of the Five Kings comes, the Tarths declare for Renly Baratheon, and Brienne wins the melee at Bitterbridge to earn her place in his Rainbow Guard.