Franks

The most successful of the Germanic barbarian peoples that invaded the Roman Empire in the 4th and 5th centuries . The Franks were a tribal confederation that emerged in the early 3rd century AD from the Chamavi, Chatturai, Salians, Tencteri and other peoples on the east bank  of the lower Rhine. The Franks began to settle on the Roman territory  west of the Rhine in the late 4th century, but their expansion was unspectacular until the reign of Clovis (r.482-511) who made them the masters of Gaul and much of Germany. Under Charlemagne (r768-814) the Franks conquered most of Christian western Europe. It was from the breakup of Charlemagne's empire, known as the Carolingican Empire, in 887-8 that the medieval kingdoms of France and Germany emerged.

Notes from Encyclopaedia of the Viking Age by John Haywood. Thames & Hudson 2000. pp 76-77.

Carolingian Empire
The Frankish empire founded by Charlemagne (r. 768-818), comprising most of Germany, France, Switzerland, Austria, the low Countries, Italy and parts of Spain and Hungary.  The empire passed intact to Charlemagne's sole surviving son, Louis the Pious, but after his death it was divided according to Frankish custom between his three sons by the treaty of Verdun in 843. The empire survived through a succession of divisions until it was reunited under Charles the Fat (r. 881-7) on whose death it broke up for good.

Notes from Encyclopaedia of the Viking Age by John Haywood. Thames & Hudson 2000. pp 40.