He is forced to take as a basis of calculation the proportion of bond to free in the only city of the Empire about which we have certain information on this point; at Pergamum there was one slave to two free persons.[327] Assuming the whole free population to have been about half a million in the time of Augustus, or rather more, including peregrini, he thus arrives at a slave population of something like 280,000; this may not be far off the mark, but it must be remembered that it is little more than a guess.
What has been said above will have given the reader some idea of the conditions of life which created a great demand for labour in the last two centuries B.C., and of the circumstances which produced an abundant supply of unfree labour to satisfy that demand.

I propose now to treat the whole question of Roman slavery from three points of view,--the economic, the legal, and the ethical.

In other words, we have to ask: (1) how the abundance of slave labour affected the social economy of the free population; (2) what was the position of the slave in the eye of the law, as regards treatment and chance of manumission; (3) what were the ethical results of this great slave system, both on the slaves themselves and on their masters.
1.

From an economical point of view the most interesting question is whether slave labour seriously interfered with the development of free industry; and unfortunately this question is an extremely difficult one to answer.

We can all guess easily that the opportunities of free labour must have been limited by the presence of enormous numbers of slaves; but to get at the facts is another matter.