The Iron Age in Norway brought significant advancements in farming, metallurgy, and seafaring. Iron tools allowed for more extensive clearing of land, which led to increased cultivation and population growth. As farming became more productive, a new social structure emerged, with extended families, or clans, offering protection and settling disputes at local assemblies known as things.
In the last century BCE, the Norse people adapted runic letters, creating their own alphabet, and began trading with the Roman Empire, exchanging furs and skins for luxury goods. Some Scandinavians even served as Roman mercenaries. During this period, powerful farmers evolved into chieftains, who acted as priests and used sacrifices to pay soldiers, establishing a personal guard, or hird, to rule over multiple clans.
The Migration Period (400–550 CE) saw an increase in chieftains' power as Germanic tribes migrated north, prompting farmers to seek protection and build fortifications. A plague in the 6th century depopulated much of southern Norway, but by the 7th century, repopulation and the growth of fishing hamlets spurred a boom in trade, particularly in iron and soapstone. By the 8th century, some chieftains controlled most of the trade, consolidating power and influence, setting the stage for the Viking Age.