Author Bryan Ayers concludes The German Ocean by describing the object of study as ‘a maritime region where the seas bind communities together rather than dividing them’. Archaeology thus gives ‘timely reminders of the importance of the European interconnectedness that is provided by the North Sea’. This is especially true of the medieval period when trade links, fostered in the two centuries prior to 1100, expanded in the twelfth and thirteenth centuries to ensure the development of maritime societies whose material culture was often more remarkable for its communalities than for its diversity. The name ‘German Ocean’ for the North Sea has its origins as Oceanus Germäic on printed ‘Ptolemy’ maps of 1477 and persisted up until the Great War. In the aftermath of Brexit, it is timely to be reminded by archaeology of the deep history of economic and cultural exchange between communities around the North Sea that, irrespective of local political climate and events, endures to the present and will doubtless continue.

From its beginnings in the mid-twentieth century, medieval archaeology has developed as an international comparative discipline with its founders and followers developing extensive research networks far beyond their immediate national boundaries. Ayers acknowledges the importance of the colloquia series Stadtarchäologie im Hanseraum (Urban archaeology in the Hanseatic region) established by the north German city of Lübeck, which has brought together archaeologists from a dozen countries on a biennial basis over the past twenty-five years to review and publish the latest discoveries from towns and settlements around the North Sea and Baltic rim. We are in the author’s debt that this extensive dataset of fieldwork and post-excavation analysis has now been brought to wider international attention.

In a nutshell, The German Ocean is a remarkable work of synthesis of the material evidence accumulated over the past forty years for the emergence of a consumerist mercantile culture in the ports and towns of the region, each exploitative of its hinterland ecologies. The book contains an extensive overview of the growth and reach of the Hanseatic commodity trade that stretched from the Gulf of Finland to the English Channel, with its distinctive ecosystem of commerce-serving urban infrastructure and housing, maritime transport, proto-industrial manufactures, architectural expression, religious devotion and commemoration, eating and drinking habits and domestic material culture. What was once the preserve of town archivists is now an interdisciplinary domain combining documentary history, buildings archaeology, iconographic studies, excavated artefacts and ecofacts and the environmental record. These trading communities were so connected through commerce, culture and kin that new ideologies, fashion trends and technologies were transmitted with speed over long distances. It is no coincidence that these increasingly mobile and diasporic merchants and artisans were responsible for the percolation into local popular culture of the revolutionary changes in design taste and in religious practice sparked by the Italian Renaissance and Lutheran Reformation respectively. Traversing many diverse specialist research areas, from the bulk trade in Rhenish stoneware jugs to fish bone distributions, the book clearly demonstrates the growing and decisive influence of archaeology on what were previously ring-fenced historical paradigms.

The value of a study such as this is the careful deployment of multiple datasets on diverse structures, materials and scientific analysis into a metanarrative of continuity and change in long-distance commercial and cultural transfer over 500 years. The archaeological record of maritime trade in a diverse catalogue of commodities, from timber, bricks, textiles, pelts and fish to domestic tableware, ceramic stoves and altar pieces, reveals the agency of the merchant in medieval society. It also highlights the transmission in cultural practice, technological innovation and design. In this way, Rhenish stoneware, which has the widest archaeological distribution of any domestic commodity across the North Sea region, can be viewed as both an indicator of long-distance commercial activity and a Kulturträger or cultural identifier in the destination context, in this case through pan-regional conformity in drinking habits. Occasionally, as in the case of medieval Novgorod, the Hanseatic station on the edge of the Russian pine zone, the archaeological record can reveal conformity to long-distance influences, but also resistance to cultural transfer. Here the distribution of German stoneware is concentrated within the enclave of foreign traders and largely absent from the indigenous settlement. The German Ocean illustrates yet again why excavated objects can be read as primary historical documents.