A 2,400-year-old timber structure found beside the Main River in Aschaffenburg, Germany, is giving archaeologists new evidence about Iron Age building skills and the importance of the nearby settlement.
High quality and complexity of the structure are clear even to the untrained eye. Credit: Björn Friedrich
Workers found the oak timbers in March 2026 during construction at a stormwater overflow basin near the Willigis Bridge. Their age was unknown at first. Scientists from the Bavarian State Office for Monument Protection soon dated the wood to the Iron Age. The trees were cut between 372 and 352 BCE.
The find is rare in both design and state of preservation. Archaeologists think the structure was built beside the river, where wet ground made construction hard. Its walls used dry-laid stone, while large oak beams formed part of the main structure.
The first third of the beams has now been removed from the excavation area. Each beam was freed by hand after careful planning. A crane then lifted the pieces from the pit. The oak beams weigh about 440 to 550 pounds each and measure around 10 to 13 feet long.
In June, archaeologists exposed the front of the structure, built from layers of stone and timber beams. Credit: Björn Friedrich
Restorers cleaned the wood before placing it in wet storage. This helps protect ancient timber after removal from waterlogged soil. Each beam will also receive a 3D laser scan. The scans will record its shape, surface, and tool marks.
Those marks already show how Iron Age workers shaped the oak. Axes and adzes left clear traces on the beams. Researchers will use these marks to study how the builders worked and how the large pieces fitted into the structure.
The purpose of the structure is still under study. Stefanie Berg, head of archaeological heritage at the Bavarian State Office for Monument Protection, said researchers think the site helped guard access from the Main River to the settlement above.
The timbers will undergo further scientific study and be conserved for future research. Credit: Björn Friedrich
A wooden platform stood between the river and the larger stone and timber structure. Researchers suggest boats might have stopped there. Goods and heavy loads could have been moved between boats and the settlement from the platform.
Building such a large site required people, materials, planning, and skilled labor. The oak trees came from the Spessart region and were worked before transport. Both timber and stone were moved along the Main River to Aschaffenburg. Workers then built the dry-stone walls and fitted the heavy beams into place.
The scale of the work points to a settlement with enough resources to organize a large building project. The site also shows skilled woodwork and building on wet ground. The structure may have served as a visible sign of the settlement’s importance.
A view of the construction site for the stormwater overflow basin in July. The fragile timbers are protected from the sun beneath plastic covers. Credit: Björn Friedrich
Several research teams are now studying the remains. Archaeologists and building researchers are examining the construction. Geoarchaeologists and archaeobotanists are studying soil layers and plant remains. Conservation specialists are preserving the wood and other finds.
More dating samples have been taken, with results still pending. The Bavarian State Office for the Environment will take adhesive profiles of the Iron Age soil in September for its soil profile collection.
The excavation is being carried out with the city of Aschaffenburg while construction of the planned pump cellar continues nearby. Archaeological work is expected to finish by the end of 2026.
Visitors will have a chance to view the excavation from above during Open Monument Day on September 13. A Bavarian State Office archaeologist will explain the work. The Stiftsmuseum will also display Celtic finds from Aschaffenburg, including objects not previously shown to the public.
More information: Bavarian State Office for the Preservation of Historical Monuments