from the Roman Period to the Middle Ages

Trading terps and Geest boundary harbours − medieval trading ports on the German North Sea coast

Frankish relief-band amphora from Groothusen, administrative district of Aurich. Photo: R. Kiepe, NIhK.

During the Early and High Middle Ages a network of trading places existed at the southern North Sea coast. Alongside individual written sources there are above all the archaeological sources which provide information about the intensity and organization of trade. The early medieval coins in particular must be cited here as direct proof of trade and money transactions. In addition a clear picture is given by the imported Rhenish pottery whose spreading along the coasts and river courses reflects the course of former traffic routes. These and other finds prove that the traders resident in the coastal area were seafarers; their trade routes followed the great water routes, on which they could travel far inland.

Trading places of the Early and High Middle Ages at the southern North Sea coast

With the early medieval trade, specialized types of settlements with different organisational structures developed at the southern North Seacoast. According to common research opinion, in the clay district (the so-called “Marsch”) traders and craftsmen lived on elongated terps (artificial dwelling mounds, so-called “Langwurten”) with a direct connection to tidal creeks and their tributary waters. However, the postulated economic orientation of these places towards trade and craft professions has so far been proved at only a few places through excavations (Emden, Groothausen amongst others). Furthermore, there existed terps whose significance for trade and crafts is indeed certain but which however do not possess the characteristic long form. Thus, in order to avoid the term “Langwurt”, which is problematic in the context of the history of research, and to separate the certain crafts and trading-terps from the settlements more strongly characterised by agriculture, the neutral term “Gewerbewurt” (trading mound or terp) has been introduced.

Area under investigation.

If we take a look at the Pleistocene hinterland, the so-called Geest, there is a series of hillforts which stand out because of their special topographical position. In contrast to the “Gewerbewurten” these places lie in those natural areas in which the tablelands of the Geest reach close to the coast or the great river courses. The architects and the function of these forts are in most cases not precisely known. However, the proximity of these places to significant land and water routes suggests that they were erected primarily to control traffic and consequently trade as well.

Aims and programme of work

Since “Gewerbewurten” as well as “Geestrand” (Geest-shore) forts were orientated towards the transport of goods via the river courses, it is to be assumed that both had harbours at their disposal. Apart from exceptions, harbours are up to now scarcely known in the area of the German North Sea coast. Therefore, the aim of this research project is to gain knew insights into the following questions:

1. Reconstruction of the topographical position of harbours

Many places which lie far away from the coast today were originally of great significance for regional and supra-regional merchant shipping. Because of dyke-building and the associated reduction of the sediment influx statements about the palaeotopographical conditions are only possible on the basis of combined investigations into the geological, vegetational and pedological development of the area. For that reason the evaluation of all published and unpublished information will stand at the start of the investigations. In addition geophysical surveys and accompanying drilling investigations are planned in order to locate the former watercourses.

2. The linking of the harbours

One aim of the project is to explain in what way harbour facilities were integrated into the contemporary settlements. Thus the question is posed whether the natural conditions were crucial to the type of linking of port facilities to the settlements, or whether the structural concepts of the users were more likely decisive for them. Another objective concerns the question whether regional or chronological peculiarities can be revealed.

3. Construction of ports

An important aim of the research project is to gain information on constructional elements connected with the loading and unloading of boats and ships. If the prospection surveys give indications of parts of construction elements, further archaeological sondages are planned to be carried out. In this case questions concerning the state of preservation, the dating, extent and function of the structures will be at the fore.

4. Chronological development of harbours

A significant aim of the project is to bring out chronological differences in the development of harbour structures and to analyse them in their socio-technological context.

5. Social and economic significance of harbours

The social and economic significance of medieval harbours has been repeatedly emphasized. However, a spatially or chronologically differentiated reconstruction of the economic and social function of coastal shipping and trade during the 7th to 12th centuries at the North Sea shore is hardly possible due to the scantiness of the available sources. Therefore at the level of certain micro-regions, which appear economically and socially consistent during the Middle Ages, all data relevant to the history of settlements will be evaluated with the help of geographical information systems in order to analyse the role of the harbours(s) within the local economic and social system. 

Micro-region of Jever with potential harbour sites.

6. Development of methods to locate and investigate harbours in the area of the North Sea coast

The various methods to be used are intended to be further developed so that they can be applied in future as routine practices in settlement research in the area of the North Sea coast and beyond. At the forefront there is the question as to which method under which conditions will produce the best results as well as which geochemical and pedological factors influence the prospection results in which way. There is special focus on the prospection of wooden constructions in solid moist sediments, which up to now has been possible only in exceptional cases.

7. Supra-reginal and diachronic comparison of the structure of harbours

As an addition to the aims described in 1-5 above, the results achieved within the framework of the project will be compared with similar finds and structures from neighbouring areas, in particular from the northern part of the Netherlands and from Denmark. This might help to understand the structure and development of medieval harbours along the southern North Sea Coast during the 7th to the 12th centuries.


Application of magnetometer surveys combined with pedological-sedimentological investigations and archaeological sondages in the environs of examined sites facilitated the localisation of former water courses, possible harbour areas as well as water management infrastructure. Additionally, it was possible to obtain information about the extent, character and density of occupation as well as the date ranges and economic development of the settlements.

During the course of the current investigations it has become apparent that coastal Wurt-settlements like Groothusen, Grimersum or Langwarden had usually been established alongside former, larger tidal creeks that existed into the early medieval period and which fell dry at low tide but which were navigable at high tide. For this reason and considered in conjunction with the archaeological data it is safe to assume a use of the watercourses and a connection to the regional waterways; however, there is as yet no irrefutable identification of harbour facilities or landing sites. At the current state of knowledge it can be assumed that suitable vessels could call at landing sites even in the absence of elaborate constructions. Furthermore, at Groothusen a man-made watercourse constructed in the Pre-Roman Iron Age demonstrates that already at an early stage the settlers impacted their environment through hydraulic engineering.  

Regarding the elongated terps (Langwurten), which are traditionally considered to be settlements of traders and craftsmen, as well as the postulated trading terps, there are only a few instances with evidence for their being established in the medieval period and for their economy being primarily targeted at trans-regional trade and commerce. In many cases there is clear evidence demonstrating that the settlements had been in existence since the Roman Iron Age and that even during the early Middle Ages their focus remained largely agrarian.

The excavations of settlements of traders and craftsmen (Cuxhaven-Sahlenburg, Witsum, Goting) located within the immediate environs of the geest-fringe forts demonstrate that these settlements, which are characterised by Grubenhäuser, were primarily engaged in diverse, small-scale crafts like smithing or textile production. It can thus be concluded that the settlements located in the environs of geest-fringe forts were not only integrated into inter-regional trading networks, but also that their economic focus was aimed at craft production. The majority of the sites investigated during the course of the project produced evidence for occupation going back to the Roman Iron Age and Migration Period.

A site near Freiburg (Elbe), discovered by the archaeological service of the district of Stade, suggests that during the early Middle Ages specialised settlements located on beach ridges and linked to beach markets benefitted from the flow of commodities across the North Sea alongside the previously mentioned trading terps and geest-fringe harbours. Consequently, the site is of great significance for future research into early medieval exchange of goods and the ports associated with it.

Future prospects

In the course of future investigations it is intended to further develop the successfully applied methodology for high-resolution palaeo-topographical reconstruction of selected sites. In addition, it is planned to more fully characterise harbours and landing sites connected to settlements by taking into account constructions intended for loading and unloading of ships.

The various economic areas and forms of social organisation within the often extensive settlements will be more closely differentiated, both temporally and spatially, in the further course of the project. The aim is to clarify which economic and social functions were fulfilled by the maritime-oriented sites within the framework of local settlement as well as within the trans-regional trade network. This will be exemplified by individual micro regions. Whether there is continuity between the early medieval sites, which are the focus of the project, and attested older structures or whether they are new foundations is another topic requiring further investigation.

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