In the thirteenth and fourteenth centuries the Crown of Aragon was a rapidly expanding and powerful political unit with an original form of representative government. Throughout this period a series of energetic and talented rulers sought to maintain royal authority and govern their realms effectively. Their persuasive rhetoric, and that of their advisers, is preserved in the archives of the Crown of Aragon in Barcelona, which provide a rich and under-exploited vein of source material for historians. There are long letters to their subjects, historical works, and the proceedings of the...