Romano-Germanic cultural contact begins as early as the first Roman accounts of the Germanic peoples. Roman influence is perceptible beyond the boundaries of the empire, in the Northern European Roman Iron Age of the first centuries AD. The nature of this cultural contact changes with the decline of the Roman Empire and the beginning Migration period in the wake of the crisis of the third century: the "barbarian" peoples of Germania Magna formerly known as mercenaries and traders now came as invaders and eventually as a new ruling elite, even in Italy itself, beginning with Odoacer's rise to the rank of Dux Italiae in 476 AD.
The cultural syncretism was most pronounced in Francia. In West Francia, the nucleus of what was to become France, the Frankish language was eventually extinct, but not without leaving significant traces in the emerging Romance language. In East Francia on the other hand, the nucleus of what was to become the kingdom of Germany and ultimately German-speaking Europe, the syncretism was less pronounced since only its southernmost portion had ever been part of the Roman Empire, as Germania Superior: all territories on the right hand side of the Rhine remain Germanic-speaking. Those parts of the Germanic sphere extends along the left of the Rhine, including the Swiss plateau, the Alsace, the Rhineland and Flanders, are the parts where Romano-Germanic cultural contact remains most evident.