 By the mid-13th century, the Emirate of Granada was the only independent Muslim realm in Spain, which survived until 1492 by becoming a vassal state to Castile, to which it paid tribute.The Kings of Aragón ruled territories that consisted of not only the present administrative region of Aragon but also Catalonia, and later the Balearic Islands, Valencia, Sicily, Naples and Sardinia (see Crown of Aragon).Considered by most to have been the first mercenary company in Western Europe, the Catalan Company proceeded to occupy the Frankish Duchy of Athens, which they placed under the protection of a prince of the House of Aragon and ruled until 1379.