As life becomes more settled and developed, there are always found families with an especial liking for war. They are enriched by the spoil which is the fruit of their bravery, and protect the agricultural and pastoral part of their tribe from the attacks of plunderers. Every nation gives willing honour to the brave warriors among them, and gladly recognises the superiority of a mode of life which puts life to the risk over other occupations. And when, from the early simple stage, in which every head of a family approaches the gods with his offerings in trust and confidence, religion has developed into a body of usages and customs which must be performed and followed out if any share is to be obtained in the grace of the gods, the exact knowledge of these can only be handed down from father to son. And if the mass of the population gives honour to the warriors, how much more readily will it bow down before those who, by their prayers, libations, and offerings, can bring them the fruits of the field and the blessing of the gods--protection in this world and salvation in the next! Moreover, if the families of warriors and priests, filled with the conviction of their own higher worth, disdain the occupations of the rest of the people; if they are convinced that they are of a better kind than the rest, that only from the noble and good can the noble and good arise--that better blood gives better feelings, and better birth better men--then in this feeling, so natural to a primitive era, they allow their occupation to be shared only by those who belong to their race; they take wives from their own class only, not from others; they give their daughters in marriage to their own people only. Thus the various modes of life and orders which naturally come into existence end in castes. The more fruitful the land of Egypt, the richer the products of the soil, and the more frequent the necessity of repelling the plundering inroads of the desert tribes, the more rapidly did the distinction between the agricultural and military orders spring up. And the greater the pride with which the inhabitants of this favoured land might and did look down upon the miserable tribes of the desert, the more grateful were the looks turned towards the gods, who had given them so beautiful and productive a land in the midst of the desert, who supplied them with water, fertilised their soil, cooled the heat of the atmosphere and gave them life and plenty, while all around them reigned desolation and death. To these beneficent powers the inhabitants of the valley of the Nile could not refuse an earnest service of thanksgiving for blessings so rich and so ceaselessly renewed; by their piety they had also to provide that the gods would graciously preserve these blessings to them. It is obvious that a tone and feeling like this, arising in the population from the very nature of the land, must have been in a high degree conducive to the rise of a priestly order in Egypt.