Strong, royalty-based nation states rose throughout Europe in the Late Middle Ages, particularly in England, France, and the Christian kingdoms of the Iberian Peninsula: Aragon, Castile, and Portugal. The long conflicts of the period strengthened royal control over their kingdoms and were extremely hard on the peasantry. Kings profited from warfare that extended royal legislation and increased the lands they directly controlled. Paying for the wars required that methods of taxation become more effective and efficient, and the rate of taxation often increased. The requirement to obtain the consent of taxpayers allowed representative bodies such as the English Parliament and the French Estates General to gain power and authority.

Along with Aragon and Castile, what Christian kingdom was present on the Iberian Peninsula?