The 6th and 5th centuries BC were a tipping point for exports and imports on the European continent. The ever-increasing conflicts and wars between the central European Celtic tribes and the Mediterranean cultures destabilized old major trade routes and networks between Scandinavia and the Mediterranean, eventually breaking them down, and changing the Scandinavian cultures dramatically. Now they had to be practically self-dependent and self-sustaining. Archaeology attests a rapid and deep change in the Scandinavian culture and way of life. Agricultural production became more intensified, organized around larger settlements and with a much more labour-intensive production. Slaves were introduced and deployed, something uncommon in the Nordic Bronze Age. The rising power, wealth and organization of the central European tribes in the following centuries did not seem to instigate an increased trade and contact between Scandinavia and central Europe before 200‒100 BC. At this point the Celtic tribes had organized themselves in numerous urban communities known as oppida, and the more stable political situation in Europe allowed for a whole new economic development and trade. Bronze could not be produced in Scandinavia, as tin was not a local natural resource, but with new techniques, iron production from bog iron slowly gained ground. Iron is a versatile metal and was suitable for tools and weapons, but it was not until the Viking Age that iron incited a revolution in ploughing. Previously, herds of livestock had pasture grazed freely in large wood pastures, but were now placed in stables, probably to utilize manure more efficiently and increase agricultural production. Even though the advent of the Iron Age in Scandinavia was a time of great crisis, the new agricultural expansions, techniques and organizations proceeded apace. And though the decline of foreign trade might suggest that the period marked a transition from a rich and wealthy culture to a poor and meagre one, the population grew and new technology was developed. The period might just reflect a change of culture and not necessarily a decline in standards of living.
Pre-Roman Iron Age. There are many bog bodies from Danish bog areas, some ritually killed, perhaps as human sacrifices, of which Tollund Man is the best-known. Their hair, skin and possessions have often been preserved in the anaerobic conditions, allowing archaeologists to learn more about their lifestyle.
In February 2020, Secrets of the Ice Program researchers discovered a 1,500-year-old Viking arrowhead dating back to the Germanic Iron age and locked in a glacier in southern Norway caused by the climate change in the Jotunheimen Mountains. The arrowhead made of iron was revealed with its cracked wooden shaft and a feather, is 17 cm long and weighs just 28 grams.
