 The Kingdom of Castile even from the 11th century "claimed a kind of sovereignty over all the princes, Christian or Moslem, of the Peninsula".The medieval Crown of Castile grew to encompass almost all of Spain outside the Crown of Aragon; even after the establishment of a joint monarchy in 1469 Castile remained distinct from Aragon up to the 18th century.Spanish was the language of the royal court and bureaucracy.