General phenomena such as the organisation of the Byzantine navy and its operations or lighthouses are discussed in this volume as well as new geoarchaeological research methodologies in harbour archaeology. Most contributions in the present volume examine case studies for the most important maritime core region of the Byzantine Empire, the Aegean. This sea connected the remaining provinces of the empire in Southeastern Europe and Asia Minor after the loss of Syria, Palestine, Egypt, and North Africa to the Arabs in the 7th century A.D. In addition to technical and geographical aspect, the studies in this volume make clear that we need to explore more and more the social embedding of the seasides of Byzantium to understand their dynamics in all their complexity. The conference »Seasides of Byzantium. Harbours and Anchorages of a Mediterranean Empire«, from which the papers collected in the present volume emerged, took place in Athens in 2017 as part of a cooperation between the DFG-funded Special Research Programme (SPP-1630) »Harbours from the Roman Period to the Middle Ages« and the National Hellenic Research Foundation. It united historians, archaeologists and geoarchaeologists to explore harbours and anchorages as core maritime infrastructure to the Late Roman and Byzantine Empire.