We have seen that the two upper classes of society were engaged in business of various kinds, and especially in banking and carrying out public contracts, or in the work of government, and in Italian agriculture.  All this business, public and private, called for a vast amount of labor, and in part, of skilled labour; the great men provided the capital, but the details of the work, as it had gradually developed since the war with Hannibal, created a demand for workmen of every kind such as had never before been known in the Graeco-Roman world.  Clerks, accountants, messengers, as well as operatives, were wanted both by the Government and by private capitalists.  In the households of the rich the great increase of wealth and luxury had led to a constant demand for helps of all kinds, each with a certain amount of skill in his own particular department; and on the estates in the country, which were steadily growing bigger, and were tending to be worked more and more on capitalistic lines, labour, both skilled and unskilled, was increasingly required.  Thus the demand for labour was abnormally great, and had been created with abnormal rapidity, and the supply could not possibly be provided by the free population alone.  The lower classes of city and country were not suited to the work wanted, either by capacity or inclination.  It was not for a free Roman to be at the beck and call of an employer, like the clerks and underlings of to-day, or to act as servant in a great household; and for a great part of the necessary work he was not sufficiently well educated.  Far less was it possible for him to work on the great cattle-runs.  And the State wanted the best years of his life for service in the army, which, as has been well remarked, was the real industry of the Roman freeman.  But luckily in one sense, and in another unluckily, for Rome, there was an endless supply of labour to be had, of every quality and capacity, for the very same abnormal circumstances which had created the demand also provided the supply.  The great wars and the wealth accruing from them in various ways had produced a capitalist class in need of labour, and also created a slave-market on a scale such as the world has never known before or since.

Ever since the time of Alexander and the wars of his successors with each other and their neighbours, it is probable that the supply of captives sold as slaves had been increasing; and in the second century B.C. the little island of Delos had come to be used as a convenient centre for the slave trade.  Strabo tells us in a well-known passage that 10,000 slaves might be sold there in a single day.[307] But Rome herself was in the time of Cicero the great emporium for slaves; the wars which were most productive of prisoners had been for long in the centre and the west of the Mediterranean basin.  All armies sent out from Rome were accompanied by speculators in this trade, who bought the captives as they were put up to auction after a battle, and then undertook the transport to Rome of all who were suited for employment in Italy or were not bought up in the province which was the seat of war.  The enormous number of slaves thus made available, even if we make allowance for the uncertainty of the numbers as they have come down to us, surpasses all belief; we may take a few examples, sufficient to give some idea of a practice which had lasting and lamentable results on Roman society.