House Estermont of Greenstone holds a small wooded island off Cape Wrath, far enough from the mainland that an Estermont lord rarely sits high at his liege's table and close enough that their fleet has often kept Cape Wrath in food when the storms have closed the roads.
Their chief claim on the kingdom's memory is that Lord Steffon Baratheon took Cassana Estermont to wife, and from that marriage came Robert, Stannis, and Renly. Cassana drowned with her lord at Shipbreaker Bay when their galley splintered on the rocks within sight of the Estermont coast, and Robert is said to have refused to look upon a green turtle in any setting from that day onward.