A metal frame allows archaeological excavations of one square metre in the tidal flats, which can be excavated and documented during one low tide. (Photo: Ruth Blankenfeldt, Schleswig)

The medieval trading center of Rungholt, which is today located in the UNESCO Wadden Sea World Heritage Site and currently the focus of interdisciplinary research, drowned in a storm surge in 1362. Using a combination of geoscientific and archaeological methods, researchers from Kiel University (CAU), Johannes Gutenberg University Mainz (JGU), the Center for Baltic and Scandinavian Archaeology (ZBSA), and the State Archaeology Department Schleswig-Holstein (ALSH), both in Schleswig, have now succeeded in locating the site of the Rungholt church. Thus, they can now finally clarify a much-discussed research question that has been going on for over 100 years.

Interdisciplinary cooperation as the key to success
Within the framework of two interdisciplinary projects funded by the German Research Foundation (DFG), i.e., the RUNGHOLT project and the Wadden Sea project in the ROOTS Cluster of Excellence, research has been conducted for several years on the medieval cultural landscape disappeared in the Wadden Sea. Well known for its mythically exaggerated destruction and an archaeological find situation unique in Europe, Rungholt is a prominent example of the effects of massive human intervention in the northern German coastal region that continue to this day.

The key to the success of the work lies in a close interdisciplinary collaboration. "Settlement remains hidden under the mudflats are first localized and mapped over a wide area using various geophysical methods such as magnetic gradiometry, electromagnetic induction, and seismics," explained Dr. Dennis Wilken, geophysicist at Kiel University. And Dr. Hanna Hadler from the Institute of Geography at Mainz University, added: "Based on this prospection, we selectively take sediment cores that not only allow us to make statements about spatial and temporal relationships of settlement structures, but also about landscape development." Archaeological investigations at selected sites provide unique insights into the life of the North Frisian settlers and repeatedly bring to light significant new finds from the tidal flats.

First large-scale reconstruction of Rungholt's drowned cultural landscape with a central church
In May 2023, a previously unknown two kilometer long chain of medieval terps, which are artificial settlement mounds, was recorded by geophysical prospection near Hallig Südfall. One of these terps shows structures that can undoubtedly be interpreted as the foundations of a church 40 meters to 15 meters in size. First corings and excavations have provided initial insights into the structure and foundations of the sacred building.

"The find thus joins the ranks of the large churches of North Frisia," stated Dr. Bente Sven Majchczack, archaeologist in the ROOTS Cluster of Excellence at Kiel University. Dr. Ruth Blankenfeldt, archaeologist at ZBSA, added: "The special feature of the find lies in the significance of the church as the center of a settlement structure, which in its size must be interpreted as a parish with superordinate function."

So far, the finds in the area investigated, which covers more than ten square kilometers, include 54 terps, systematic drainage systems, a sea dike with a tidal gate harbor as well as two sites of smaller churches – and now also a large main church. The settlement area found must therefore be regarded as one of the historically reported main sites of the medieval administrative district of Edomsharde.

Erosion threatens cultural remains
In addition to the unique archival character that the mudflats have for the reconstruction of Rungholt's cultural landscape, the project results of recent years also show the extreme endangerment of the cultural traces that are over 600 years old. "Around Hallig Südfall and in other mudflats, the medieval settlement remains are already heavily eroded and often only detectable as negative imprints. This is also very evident around the church's location, so we urgently need to intensify research here", emphasized Dr. Hanna Hadler.

Research projects in the North Frisian Wadden Sea
The research within the framework of the DFG-funded project "RUNGHOLT – Combined geophysical, geoarchaeological, and archaeological investigations in the North Frisian Wadden Sea in the vicinity of the medieval trading centre of Rungholt" is a joint effort of Dr. Hanna Hadler and Professor Andreas Vött of the Natural Hazard Research and Geoarchaeology group at Mainz University, Dr. Dennis Wilken of the Applied Geophysis group at Kiel University as well as Dr. Ruth Blankenfeldt of the Center for Baltic and Scandinavian Archaeology in Schleswig and Dr. Stefanie Klooß and Dr. UIf Ickerodt of the State Archaeology Department Schleswig-Holstein. Furthermore, Dr. Bente Sven Majchczack und Professor Wolfgang Rabbel cooperated within the project "Socio-environmental Interactions on the North Frisian Wadden Sea Coast" in the ROOTS Cluster of Excellence of Kiel University.

A lightweight measuring cart provides large-scale magnetic mapping of cultural traces hidden beneath the surface of today's mudflats. (Photo:Dirk Bienen-Scholt, Schleswig)

Sediment cores are taken to record settlement remains and reconstruct landscape development at selected sites on the tidal flats. (Photo: Justus Lemm, Berlin)

Publication about the project
Wilken, D., Hadler, H., Wunderlich, T., Majchczack, B., Schwardt, M., Fediuk, A., Fischer, P., Willershäuser, T., Klooß, S., Vött, A. & Rabbel, W. (2022). Lost in the North Sea—Geophysical and geoarchaeological prospection of the Rungholt medieval dyke system (North Frisia, Germany). Plos one, 17 (4), https://doi.org/10.1371/journal.pone.0265463

More information:
Website of the  des ALSH
Website of the "Applied Geophysics" group at Kiel University
Website of the Geopmorphology group at the JGU Institute of Geography
The Wadden Sea project of the Cluster of Excellence ROOTS
Information on the Rungholt project on the DFG website
Website of the ZBSA

Press contact
Jan Steffen
Media and Public Outreach, Cluster of Excellence ROOTS
jsteffen@roots.uni-kiel.de
+49 (0)431/880-5485
to the website

Scientific contact in Kiel:
Dr. Dennis Wilken
Institute for Geosciences at Kiel University
+49 431 880-4648
dennis.wilken@ifg.uni-kiel.de

Dr. Bente Majchczack
Cluster of Excellence ROOTS at Kiel University
+49 431 880-6705
bmajchczack@roots.uni-kiel.de

Scientific contact in Mainz:
Dr. Hanna Hadler
Institute of Geography at JGU Mainz
+49 6131 39-24496
hadler@uni-mainz.de

Scientific contact in Schleswig:
Dr. Ruth Blankenfeldt
Centre for Baltic and Scandinavian Archaeology
+49 4621 813 – 289
ruth.blankenfeldt@zbsa.eu