The emergence of the Imperial cult and its role in provincial diplomacy have been much studied by Roman scholarship. In general, the balance is tipped in favour of studies of public practice, although private practice has certainly also been on the scholarly agenda. However, the role of emperor worship in overseas commerce has received precious little attention. The evidence is admittedly thin (I lay no claim to being comprehensive in my treatment here). Moreover, absent above all are documentary data, the type of source material that would have been most useful and that scholars of more recent time periods have access to, for instance in the form of private business letters. Nonetheless, what has survived is in my view intriguing and worth discussing jointly, an endeavour that to my knowledge has never been attempted.