In modern political and economic discussions we are apt to talk rather glibly of “labour.” Much has been made of the _solidarity of labour_ and its sense of community. It is well to note that in these first civilizations, what we speak of as “labour” is represented by five distinct classes dissimilar in origin, traditions, and outlook--namely, classes 3, 4, 5, 9, 10, and the oar-tugging part of 12. The “solidarity of labour” is, we shall find when we come to study the mechanical revolution of the nineteenth century A.D., a new idea and a new possibility in human affairs. § 5 Let us, before we leave this discussion of the social classes that were developing in these first civilizations, devote a little attention to their fixity. How far did they stand aloof from each other, and how far did they intermingle? So far as the classes we have counted as 9, 10, 11, and 12 go, the servants, the gang labourers and slaves, the gang soldiers, and, to a lesser extent, the sailors, or at any rate the galley rowers among the sailors, they were largely recruited classes, they did not readily and easily form homes, they were not distinctively breeding classes; they were probably replenished generation after generation by captives, by the failures of other classes, and especially from the failures of the class of small retailers, and by persuasion and impressment from among the cultivators. But so far as the sailors go, we have to distinguish between the mere rower and the navigating and shipowning seamen of such ports as Tyre and Sidon. The shipowners pass, no doubt, by insensible gradations into the mercantile class, but the navigators must have made a peculiar community in the great seaports, having homes there and handing on the secrets of seacraft to their sons. The eighth class we have distinguished was certainly a precarious class, continually increased by the accession of the heirs and dependents, the widows and retired members of the wealthy and powerful, and continually diminished by the deaths or speculative losses of these people and the dispersal of their properties. The priests and priestesses too, so far as all this world west of India went, were not a very reproductive class; many priesthoods were celibate, and that class, too, may also be counted as a recruited class. Nor are servants, as a rule, reproductive. They live in the households of other people; they do not have households and rear large families of their own. This leaves us as the really vital classes of the ancient civilized community: (_a_) The royal and aristocratic class, officials, military officers, and the like; (_b_) The mercantile class; (_c_) The town artisans; (_d_) The cultivators of the soil; and (_e_) The herdsmen.