challenge posed by maintaining a constant supply of would-be slaves. In
a recent survey of the topic, Jean Andreau and Raymond Descat have
concluded that perhaps half the population of some of the larger,
wealthiest ancient cities, including Athens and Rome, consisted of slaves,
although this proportion was by no means stable. From the midfirst
centurybc, the number of slaves in many Italian towns is estimated at
between 30 and 40 per cent. However, most scholars now agree that the
presence of slaves in different centres of population probablyfluctuated
quite markedly. Outside the major centres of slave consumption, their
presence may well have been far smaller, in many places negligible.
Slaves could provide useful labour; in the home, in the countryside, or
in physically exhausting or unattractive production processes, including
mining, tanning, fulling, pottery and other crafts. However, this required
capital investment for the slave owner, an investment that could not be
guaranteed, because of high mortalityfigures and the high variation in
slave prices. Viewed in these terms, slaves represented an additional
source of potential rent for the slave owner, rather than a source of
productive endeavour.^83 Enslavement resulted from violent confronta-
tion—usually in the context of military defeat or opportunistic kidnap-
ping. There was always, therefore, a degree of exceptionalism about the
circumstances for creating new slaves. The enslavement of foundlings
and the fostering of children born to existing slaves were probably
important alternative methods of generating new stock and are increas-
ingly being recognized as mechanisms for satisfying demand.^84 Slavery
and slave ownership were factors of economic and social interchange.
They belonged to the money economy and the market, even if they
were acquired by piracy or by other forcible means. So slaves belonged
to accountants’ balance sheets as much as they did to command
structures.
Historians have often drawn attention to the origins of slaves in
Thrace, so the significance of slavery in the economies of the north
Aegean deserves particular consideration. Many of the slaves that feature
in Attic comedy, and infifth- and fourth-centurybcAttic inscriptions,
were calledThraixandThraitta, implying an origin somewhere in
Thrace. This is more than a stereotype; it is a conventional way of
disguising genuine connections, whilst providing a plausible-sounding
ibid. 49–55, on direct forced labour; 71–9 on Aristotle’s evaluation of labour; 140–204,
slavery and‘unfree’categories of labour).
(^83) Andreau and Descat 2006, 65–105 on slave numbers; 146–51 for the comparative
attractiveness v. lack of attraction of slave ownership.
(^84) Andreau and Descat 2006, 92–4; Lewis 2011, 109.
Societies and economies 119