In the regions of Denmark where the farmer had access to forest and to bog ore of good quality, the production of sponge, refining and forging were integral parts of the work of the year – from the beginning of the Iron Age to well into the Middle Ages. Throughout all these years iron technology was primarily associated with the rural population and civilian concerns. But at intervals it also attracted military and commercial attention from magnates, chieftains and kings. For access to the good iron qualities was the very basis of good craftsmanship and good craftsmanship conferred power, locally and regionally.
Theoretically, the increased iron consumption in the Late Germanic Iron Age could have been based exclusively on imported iron. But given the extensive, widespread production shortly before this, the argument does not seem tenable. Many smelters and smiths in the sixth century had a highly developed familiarity with the iron technology processes and this insight – also under stable political, economic and social conditions – would be more likely to result in the development of new and more sophisticated technology than in a cessation of production. Analyses of slag inclusions in the iron from knives dated to the Late Germanic Iron Age and Viking Age support this argument.
Danish bog iron was not forged in standardized bar types, which may be because most of it never moved far from the place where it was extracted. A demonstration of the iron quality was not necessary when smelter and smith was the same farmer, and this underscores the local nature of iron technology.
In connection with metallurgical analyses systematic experimental work has proved to be of great value. The experiments were an adequate tool not only for the study of iron technology, but also for exploring the working processes that took place in prehistoric and early historical society. But the tempting yield calculations – such as that
100 kg of roasted bog ore can be reduced to 10 kg of iron sponge which can be refined to 2 kg of iron bars, which can then be forged into 1.5 kg implements – tell us more about the experimental work of the present day than about the skills of the old smiths and smelters.
Text: H. Lyngstrøm