126 THE ROMAN DOMINION Slavery. Through the entire period of ancient history— usually reckoned as ending with the disappearance of a Roman emperor from Italy — the whole structure of society rested on the basis of slavery. From Hammurabi to Justinian, slavery was a recognised institution in Babylon and Athens and Rome alike, as it was in Egypt. The more complicated and elaborate the order of society was, the more prominent was the slave element. An immense proportion of the population consisted of slaves ; that is, persons, male and female, who were as much the property of their owners as sheep and cattle. Captives in war whose lives were spared became in the first instance the slaves of their captors as a matter of course, and the children of slaves continued to be slaves. Slavery also might be the penalty of debt and sometimes of crime. Freedom was obtained either by the deliberate act of the owner in setting the slave free, or by purchasing freedom, as slaves were commonly allowed to acquire property. The bulk of the severest and meanest forms of labour was done by slaves ; and it was a constant grievance of the poorer classes of those who were free that slave labour excluded paid labour, and they themselves were in constant danger of being reduced to slavery by incurring debts which they could not pay. Christianity tended to diminish the rigours of slavery, which in the Middle Ages and in Christian regions was replaced by serfdom, as to which a further note will be found on page 169.
