Analysis of information sources in references of the Wikipedia article "Slavery in ancient Rome" in English language version.
Recent studies of Italian demography have further increased doubts about a rapid expansion of the peninsula's servile population in this era. No direct evidence exists for the number of slaves in Italy at any time. Brunt has little trouble showing that Beloch's estimate of 2 million during the reign of Augustus is without foundation. Brunt himself suggests that there were about 3 million slaves out of a total population in Italy of about 7.5 million at this date, but he readily concedes that this is no more than a guess. As Lo Cascio has cogently noted, that guess in effect is a product of Brunt's low estimate of the free population