Frankish

The Franks were a group of Germanic peoples, whose name was first mentioned in 3rd century Roman sources, associated with tribes on the Lower and Middle Rhine, on the edge of the Roman Empire.
The Frankish state consolidated its hold over the majority of western Europe by the end of the 8th century, developing into the Carolingian Empire.

With the coronation of their ruler Charlemagne as Holy Roman Emperor by Pope Leo III in 800 AD, he and his successors were recognised as legitimate successors to the emperors of the Western Roman Empire.