The Frisians are the main reason the Romans were kept mostly south of the Rhine; about 450 they crossed the North Sea and invaded England, settling in Kent, East Anglia and Lincolnshire. They remained an important force from the latter part of the Roman period through about 800 AD, when Charlemagne conquered most of Europe. Since then, they continue to keep their cultural identity and language alive today.
Cunliffe, Barry. 1994. Barbarian Europe. In Prehistoric Europe: An Illustrated History. Oxford University Press, Oxford.
This glossary entry is part of the Dictionary of Archaeology. Thanks to Johannes van den Heuvel for information on the Frisians.