The origin of the Germanic peoples remains somewhat of a mystery. Their language and culture are Indo-European, but how and when they arrived in Northern Europe is not clear. Unequivocal archeological evidence for a Germanic culture does not antedate the Harpstedt and Jastorf Cultures. These two closely related cultures (named for the towns where the archeological digs occurred) emerged c. 500 BCE. This date agrees with linguists' calculations for the date of the language changes that mark Germanic as a distinct branch of Indo-European. The evidence would place the Germanic "homeland" in northern Germany and parts of Denmark, which is where the Classical World first encountered Germanic peoples according to the earliest accounts, written between 100 BCE and 100 CE.

Germanic culture seems to have arisen in situ. The archeological record bears no evidence of a large-scale intrusion of Indo-Europeans circa 500 BCE. The Harpstedt/Jastorf Cultures show continuity with the earlier, widespread Corded Ware Culture, which embraces the "homelands" of the Germanic and Balto-Slavic peoples,as well as the Celtic and perhaps even the Italic culturesl -- and all of these languages share similarities not otherwise found in Indo-European. Thus some scholars have seen an earlier "Indo-European invasion" from which several linguistically distinct subgroups later emerged. The evidence for a sudden arrival is not compelling. This Corded Ware Culture, in turn, shows continuity with the Globular Amphora Culture and even back to Funnel-Beaker Culture. Two possible explanations remain. One possibility is that the Funnel-Beaker Culture was itself Indo-European, which would mean an Indo-European presence by c. 4500 BCE or even earlier. This extremely early date runs counter to much of the currently available linguistic and archeological evidence about the spread of Indo-European culture, but it does have its proponents. A currently popular view favors the model of comparatively small groups of Indo-Europeans slowly penetrating the area. Sometimes, when pastoral and agriculture societies come in contact, the pastoral group tends to have the economic advantage (at least in the short term), and so most cultural borrowing is from pastoralist to agriculturist. This phenomenon might explain how Northern and Central Europe could become Indo-Europeanized even though numerically the pastoral Indo-Europeans were a minority. If, as seems likely, the Indo-European arrival into northern Europe was a slow trickle rather than a sudden invasion, it occurred over a long period of time. One model with considerable evidence to support it is that by the time of Corded Ware Culture the Indo-European presence is showing its influence. In addition to the Indo-European influence from the east, a non-Indo-European megalithic culture from western Europe was also in the area. Germanic culture emerged as the two groups melded.

Whenever and however the Indo-Europeans arrived in North-Central Europe, we are left with the fact that a distinctively Germanic culture did not emerge until c. 500 BCE. Over the centuries, Germanic tribes expanded south and east across central Europe. By c. 400 CE the Roman Empire faced Germanic tribes along its two riverine borders, the Rhine and the Danube. The Western Roman Empire was in a weakened state, and the explosive Germanic expansion known as the "Age of Migrations" was about to begin.