Introducing the volume to come, this chapter explains the need for new approaches to the study of literary and cultural interactions in the Roman empire that cross linguistic, cultural and religious boundaries. It begins with a brief overview of the diversity of cross-cultural interactions that can be traced, on and off the page, between different individuals and communities in the second century CE. It analyses current and innovative methodologies for studying ‘intertextuality’ in different disciplines, including approaches that amplify gaps or silences, as well as instances of dialogue/cross-fertilisation. It then stresses three ways in which the volume particularly aims to contribute: firstly, by including technical, documentary, epigraphic and oral material in its wide-ranging study of ‘literary’ interactivity; secondly, by stressing the relationship between textual interaction, cultural practices and material aspects of empire; thirdly, by working out from intertextuality to interdiscursivity, shining a spotlight on the migration of ideas as well specific interactions. The introduction ends with a case study – the story of Arion and the dolphin, retold by many ancient authors – that exemplifies the processes of cross-cultural travel and transmission in the ancient world and also the challenges that scholars face in tracing and interpreting such cross-cultural interactions.

When did kosmos come to mean ‘world-order’? This chapter ventures a new answer by examining evidence in late doxographies and commentaries often underutilized or dismissed by scholars. Two late doxographical accounts in which Pythagoras is said to be first to call the heavens kosmos (in the anonymous Life of Pythagoras and the fragments of Favorinus) exhibit heurematographical tendencies that place their claims in a dialectic with the early Peripatetics about the first discoverers of the mathematical structure of the universe. Xenophon and Plato refer to ‘wise men’ who nominate kosmos as the object of scientific inquiry into nature as a whole and the cosmic ‘communion’ (koinônia) between all living beings, respectively. But Empedocles is the earliest surviving source to use kosmos to refer to a harmonic ‘world-order’ and to illustrate cosmic ‘communities’ between oppositional pairs, realizing the mutual correspondence in the cycle of love and strife. Thus, if later figures posited Pythagoras as the first to refer to the universal ‘world-order’ as the kosmos, they did so because they believed Empedocles to have been a Pythagorean natural scientist, whose combined focus on cosmology and ethics was thought to exemplify a distinctively Pythagorean approach to philosophy.