The settlement took the form of a large artificial Island surrounded by 450m of timber ramparts enclosing about 100 identical houses, laid out on a strict grid pattern separated by timber streets. The whole structure was very regular and built from standardised components. It dated to the Hallstatt period, but belonged to a northerly contemporary, the Lusatian culture, which is evident in the area immediately south of the Baltic, particularly in Poland. Modern dendrochronology dates the felling of many of the oak trees used at Biskupin to the winter of 738/737 BC. (Radiocarbon dating in the 1980s had placed the site up to a century earlier, which, not for the first time, was the cause of some confusion.)
The defences were ‘box ramparts’, a type common in this period, constructed using parallel walls of logs, linked by cross pieces, with the space between them filled with earth. At Biskupin this timber and earth wall was 3.5 m thick, and beyond it was a timber breakwater of driven stakes. This would have prevented the approach of boats from the lake, and helped protect the artificial island from erosion. The breakwater was about half a kilometre long, and it required an estimated 18,000 to 20,000 stakes, representing about 4000 trees. The site as a whole required a huge amount of timber, and a large area of woodland and forest must have been harvested.
The lack of social distinction evident in the houses was surprising, and the regularity of plan and use of standardised components was more like something constructed by the Roman army, and confounded the popular view that Iron Age Europe was somehow wild, undisciplined, and individualistic.
The site was renamed "Urstädt", and excavations were resumed by an extraordinary branch of the SS called the ‘SS Ahnenerbe’. This was a unit of crack Nazi anthropologists and scholars, under the control Heinrich Himmler. They spent the war looting museums, art galleries and churches, as well as conducting excavations in pursuit of their Aryan ancestors, and later even turned their hand to a bit human experimentation. The Nazi perspective was that ancient Biskupin was a primitive Polish settlement overrun and rebuilt by superior Aryan culture.
In 1944 the Germans, retreating, made some attempt to destroy the site, including flooding it, which unintentionally helped preserve it. After the war excavation returned to Polish control, and over the next 30 years the site was full excavated, and it is now an archaeological park and centre for experimental archaeology.
The involvement of the Nazis, and even the site's importance to Polish nationalism, highlights the problems of contemporary cultural bias in the interpretation of archaeology. This issue, probably more than any other, has concerned post-war archaeologists, and has given rise to much intellectual angst and navel gazing among the theoretically inclined.
Theoretical structural archaeology is the study of lost built environments, in particular timber structures, so to actually find one is profoundly important. The insight into building technology and carpentry is invaluable, especially if we are not too concerned about whether Biskupin was ‘typical’ of structures built on lakes or of building in general.