the people repopulating a town. The fueros provided a means of escape from the feudal system, as fueros were only granted by the monarch. As a result, the town council was dependent on the monarch alone and, in turn, was required to provide auxilium – aid or troops – for their monarch. The military force of the towns became the caballeros villanos. The first fuero was given by count Fernán González to the inhabitants of Castrojeriz in the 940's. The most important towns of medieval Hispania had fueros, or forais. In Navarre, fueros were the main repopulating system. Later on, in the 12th century, Aragon also employed the system; for example, the fuero of Teruel, which was one of the last fueros, in the early 13th century. From the mid-13th century on, no more charters were granted, as the demographic pressure had disappeared and other means of re-population were created. Fueros remained as city charters until the 18th century in Aragon, Valencia and Catalonia and until the 19th century in Castile and Navarre. Fueros had an immense importance for those living under them, who were prepared to go to war to defend their rights under the charter. In the 19th century, the abolition of the fueros in Navarre would be one of the causes of the Carlist Wars. In Castile, disputes over the system contributed to the war against Charles I (Castilian War of the Communities). Christian military culture Motivations Jim Bradbury (2004) noted that the Christian belligerents in the Reconquista were not all equally motivated by religion, and that a distinction should be made between 'secular rulers' on the one hand, and on the other hand Christian military orders which came from elsewhere (including the three main orders of Knights Templar, Knights Hospitaller and Teutonic Knights), or were established inside Iberia (such as those of Santiago, Alcántara and Calatrava). '[The Knights] were more committed to religious war than some of their secular counterparts, were opposed to treating with Muslims and carried out raids and even atrocities, such as decapitating Muslim prisoners.' On the other hand, Christian armies sometimes forged temporary alliances with Islamic emirs, and Christian mercenaries were quite willing to fight for Arab and Berber rulers if the price was right. El Cid is a well-known example of a Christian mercenary leader who was in paid military service of the Islamic kings of Zaragoza for years. Mercenaries were