The preference of the Admin is for the players to have read at least A Game of Thrones. However, Open characters are available to players with no familiarity with the theme, provided that they have prior MUSHing experience as the game is not setup to cater to players who lack both thematic knowledge and MUSHing experience.
Furthermore, the preference of the Admin is that players have read at least A Storm of Swords and preferably also A Feast for Crows to apply for Dornish characters.