Far to the South of Westeros, past Dorne, there is a Queendom that has remained outside of the affairs of those who do not belong. They have no true affiliations or alliances though they are, on accession, friendly with some. Because they were powerful enough that they could withstand the initial Targaryen establishment of the Seven Kingdoms , they were forgotten.
Until Now.....
*this initial Idea I got from one of the many GOT books in my reading list. if you thing it might be too similar to yours, please check there and let me know because i don't want to plagiarize and tack credit when it's not my work*