Pascal Arnaud is Emeritus Professor Roman History at the Université Lumière Lyon II and a senior Fellow at Institut Universitaire de France. His main fields of expertise are maritime history, economic history, epigraphy, papyrology, ancient geography and periplography. He has been co-directing the ERC Advanced Grant-funded Portus Limen project which has been investigating ports across the Mediterranean. Simon Keay is Professor of Roman Archaeology at the University of Southampton and a Fellow of the British Academy. His main areas of expertise are Roman trade, commerce and cultural change. Most recently, he has been directing excavations and survey at Portus, the port of imperial Rome, as well as the ERC Advanced Grant-funded Portus Limen project which has been investigating ports across the Mediterranean.