During the 10th century and onwards, cities and towns gained more importance and power, as commerce reappeared and the population kept growing. "Fueros" were charters documenting the privileges and usages given to all 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.