Historians of western antiquity have increasingly come to rely on the comparative method in their attempts to gain a better understanding of slavery in the ancient Mediterranean. There are good reasons for this. Slavery was widespread in western antiquity and rose to great importance in the two ancient societies we know most about – Athens and Rome – but there is a tantalizing shortage of data on the subject. Clio has been especially cruel to classical historians, giving them just enough information to confirm that slavery was important in many ancient states but not enough to go beyond informed guesses.

In situations such as this, the comparative method is the only recourse after having exhausted what we can learn from the available evidence. By comparing what we know about ancient slavery with other kinds of slaveholding societies, we might be able to situate both the institution and its social context within broader classificatory frameworks that might shed light on the ancient cases. In many ways, this is no different from what archaeologists do. Indeed, given the importance and long acceptance of archaeology – an inherent comparative discipline – in the study of the ancient world, it is puzzling that it took so long for social and economic historians of antiquity to turn to the comparative approach as a method of supplementing and helping to make sense of their subject.