The perfect settlement of the Roman empire was preceded by ages of violence and rapine.

The slaves consisted, for the most part, of barbarian captives, * taken in thousands by the chance of war, purchased at a vile price, accustomed to a life of independence, and impatient to break and to revenge their fetters.

Against such internal enemies, whose desperate insurrections had more than once reduced the republic to the brink of destruction, the most severe regulations, and the most cruel treatment, seemed almost justified by the great law of self-preservation.

But when the principal nations of Europe, Asia, and Africa were united under the laws of one sovereign, the source of foreign supplies flowed with much less abundance, and the Romans were reduced to the milder but more tedious method of propagation.

* In their numerous families, and particularly in their country estates, they encouraged the marriage of their slaves.