The clergy was divided into two types: the secular clergy, who lived out in the world, and the regular clergy, who lived under a religious rule and were usually monks. Throughout the period monks remained a very small proportion of the population, usually less than one per cent. Most of the regular clergy were drawn from the nobility, the same social class that served as the recruiting ground for the upper levels of the secular clergy. The local parish priests were often drawn from the peasant class. Townsmen were in a somewhat unusual position, as they did not fit into the traditional three-fold division of society into nobles, clergy, and peasants. During the 12th and 13th centuries, the ranks of the townsmen expanded greatly as existing towns grew and new population centres were founded. But throughout the Middle Ages the population of the towns probably never exceeded 10 per cent of the total population.