It is hard to get any agreement on the accurate meaning of the term "social class". In everyday life, people tend to have a different approach to those they consider their equals from that which they assume with people they consider higher or lower than themselves in the social scale. The criteria we use to "place" a new acquaintance(熟人) , however, are a complex mixture of factors. Dress, way of speaking, area of residence in a given city or province, education and manners all play a part. In Greece, after the sixth-century B. C. , there was a growing conflict between the peasants and the landed aristocrats (贵族) , and a gradual decrease in the power of the aristocracy when a kind of "middle class" of traders and skilled workers grew up. The population of Athens, for example, was divided into three main classes which were politically and legally distinct. About one-third of the total were slaves, who did not count politically at all, a fact often forgotten by those who praise Athens as the nursery of democracy. The next main group consisted of resident foreigners, the "metics", who were freemen, though they two were allowed no share in political life. The third group was the powerful body of "citizens", who were themselves divided into sub-classes. In tile later Middle Ages, however, the development of monetary economy and the growth of cities and trade led to the rise of another class, the "burghers" or city merchants and mayors. These were the predecessors of the modern middle classes. Gradually high office and occupation assumed importance in determining social position, as it became more and more possible for a person born to one station in life to move to another. This change affected the towns more than the country areas, where remnants of feudalism lasted much longer. With the break-up of the feudal economy, the increasing division of labour, and the growing power of the town burghers(公民) , the commercial and professional middle class became more and more important in Europe, and the older privileged class, the landed aristocracy, began to lose some of its power. The best title of the passage might be______.