House Martell
Princes of Dorne, joined to the Iron Throne at last — not by conquest but by King Daeron's two marriages: his Myriah for the realm, his sister Daenerys for Prince Maron. Half the realm's grumblers call the king half-Dornish for it, and drank to Daemon Blackfyre once because of it.
The fuller tale
Dorne came late and strangely to Westeros — not with the First Men or the Andals, but centuries later with Nymeria and her Rhoynish refugee fleet, who burned their own ships on the Dornish shore rather than sail on and married their queen into the Martell line, bringing with them a legal habit no other kingdom shares: inheritance by eldest child regardless of sex, a custom that has made Dornish succession a genuine oddity in Westerosi eyes ever since.
It also made Dorne the one kingdom Aegon the Conqueror's dragons could not simply burn into submission — guerrilla resistance, poisoned water, and a refusal to meet fire in open battle wore down a conquest that worked everywhere else almost instantly, and a century later a second attempt under Daeron I the Young Dragon conquered the sun-and-spear kingdom outright only to lose it again in a bloody uprising within a few years. Unbowed, Unbent, Unbroken is not a boast so much as a documented track record.
What no army ever managed, Daeron II achieved twice over at the altar: his own marriage to Myriah Martell and his sister Daenerys's marriage to Prince Maron Martell brought Dorne into the Seven Kingdoms at last, peacefully, a full century after the dragons first tried and failed to take it by force — arguably the single most consequential diplomatic act of his entire reign.
Not every lord in the realm has made peace with the arrangement even now. Grumblers still needle the king as half-Dornish behind his back, and some of the same disappointed men who once drank to Daemon Blackfyre did so partly out of resentment at a match they never wanted — which makes the Martells, oddly, both the era's great diplomatic triumph and one of the quiet grievances still feeding its unfinished rebellion.
The page and the screen
Dorne itself has not appeared as a setting in the aired season, whose action stays in the Reach; the marriages that bound Dorne to the Iron Throne belong to background history the novellas reference rather than dramatize, and remain unadapted on screen.