what are the four main houses in game of thrones?
["Targaryen of King's Landing.", 'Stark of Winterfell.', 'Lannister of Casterly Rock.', 'Arryn of the Eyrie.', 'Tully of Riverrun.', 'Greyjoy of Pyke.', "Baratheon of Storm's End.", 'Tyrell of Highgarden.']