Archaeologists have begun recovering massive oak timbers from a remarkably well-preserved Iron Age structure discovered beside the River Main in Aschaffenburg, a find that could shed new light on Celtic engineering, trade and settlement activity more than 2,400 years ago.
The ancient structure was discovered unexpectedly in March during construction of a storm-water overflow basin near the city’s Willigis Bridge. Workers encountered substantial wooden remains whose age and significance were initially unknown.
Within weeks, specialists from the Bavarian State Office for Monument Preservation (BLfD) dated the oak beams to between 372 and 352 BC, establishing the site as an exceptional Iron Age discovery. According to the BLfD, the combination of its age, construction and extraordinary state of preservation makes the complex unique not only in Bavaria but across Germany.
First Ancient Beams Lifted from Excavation
After months of preparation by archaeologists, conservators and scientists, teams have now recovered roughly a third of the surviving timbers.
Each beam was carefully detached by hand before being lifted from the excavation by crane. The individual oak timbers measure between three and four metres long and weigh approximately 200 to 250 kilograms.
Following removal, conservation specialists cleaned the waterlogged wood and prepared it for wet storage, which will help prevent the ancient timbers from deteriorating as they are studied.
Researchers will next produce detailed 3D laser scans of every beam. Tool marks still visible on the wood, including traces left by Iron Age axes and adzes, are already providing researchers with evidence of the woodworking methods used by Celtic craftspeople.
Plans are also being developed to conserve and eventually display part of the timber structure and its associated stone wall at Aschaffenburg’s Stiftsmuseum.
Was the Structure an Ancient Riverside Gateway?
Although researchers have yet to determine exactly what the structure was used for, the excavation is producing new clues.
One possibility is that the substantial timber-and-stone construction protected an access route connecting the Main with a settlement above the river.
“We do not yet know the structure’s purpose,” said Dr Stefanie Berg, Head of the Archaeological Heritage Department at the BLfD.
Researchers have identified a wooden platform on the river-facing side of the structure, raising the possibility that boats once stopped there to unload or transfer goods and cargo.
The main construction itself incorporated substantial dry-stone walls and an elaborate framework of heavy timber beams.
If the interpretation proves correct, the site could provide important evidence of how the settlement interacted with traffic and commerce along the Main during the Iron Age.
A Major Celtic Engineering Project
The scale of the construction suggests it was far from an improvised riverside installation.
Researchers believe its builders deliberately adapted the structure to cope with difficult, damp ground conditions. Constructing it would have required extensive planning, skilled labour and the ability to organise significant quantities of raw materials.
The oak trees are thought to have been felled and worked in the Spessart region before being transported along the Main to the construction site. Stone used for the walls was also brought in, while the enormous timbers had to be precisely fitted into the wooden framework.
“A structure like this wasn’t built casually,” Berg said, noting that it would have demanded a large workforce and immense effort.
Its imposing appearance may have served another purpose. Visible from the river, the structure could have acted as a conspicuous statement of the settlement’s importance and the power of the community responsible for building and protecting it.
Discovery Could Reshape Understanding of Iron Age Construction
The significance of the excavation could extend well beyond Aschaffenburg.
Archaeologists and architectural researchers are studying the construction itself, while geoarchaeologists and archaeobotanists are examining sediments, soil layers and surviving plant material. Conservation experts are simultaneously securing and analysing artefacts and structural remains.
Additional samples have been taken for scientific dating, with results still pending.
The Bavarian Environment Agency is also participating in the project and plans to produce adhesive profiles of the Iron Age soil layers during September for inclusion in its soil profile collection.
Taken together, the evidence is beginning to paint a picture of a settlement capable of organising workers, acquiring distant materials and deploying highly skilled craftspeople on a major infrastructure project.
That organisational capacity points to Aschaffenburg’s considerable regional importance around 2,500 years ago.
Archaeological investigations are continuing in coordination with the City of Aschaffenburg, while construction of the planned pump cellar proceeds alongside the excavation. Archaeological work at the site is expected to be completed by the end of 2026.
Public to Get a Look at the Excavation
Members of the public will have an opportunity to see the archaeological site during Germany’s Open Monument Day (Tag des offenen Denkmals) on 13 September.
Visitors will be able to view the excavation from above, while a BLfD archaeologist will explain the discoveries and ongoing research. The Stiftsmuseum will also exhibit Celtic finds from Aschaffenburg that have not previously been shown to the public.
Tours are due to be bookable through the City of Aschaffenburg, with registration expected to open shortly.
More than two millennia after its builders carefully fitted massive oak beams together beside the Main, the riverside complex is emerging again — and could provide researchers with an unusually detailed glimpse into the engineering skill, economic organisation and ambitions of an Iron Age community.
Header Image Credit : Björn Friedrich
Sources : Bavarian State Office for the Preservation of Historical Monuments
