The relationship between demographic structures and economic performance in classical antiquity is a remarkably neglected subject; it is only very recently that a few scholars such as Walter Scheidel have begun to address such issues. Studies of the ancient economy remained fixated for decades on the unanswerable but seductive question of how far antiquity could be considered ‘modern’, understood in terms of an under-analysed assortment of phenomena such as large-scale inter-regional trade in staples, systems of banking and credit, a rational approach to profit-making and the development of market-orientated industry, or primitive, agrarian and underdeveloped. Even as historians have sought to escape this false dichotomy and developed more sophisticated conceptions, not least by recognising both the strict ‘limits of the possible’ within a pre-industrial economy and the scope for wide variation in economic organisation and performance within those limits, little attention has been paid to demography, except occasionally as a basis for highly speculative estimates of the GDP of the Roman Empire; there is certainly no obvious sense that change, not only in absolute numbers but in structures and processes, might be a, or indeed the, significant source of change in the economic sphere. ‘Demography’ is included as one of the ‘determinants of economic performance’ in the first section of the Cambridge Economic History of the Greco-Roman World, but most of its subsequent chapters nevertheless manage to limit their consideration of the subject to the usual estimates of overall numbers as an indicator of prosperity or crisis.