Old Frisian

Old Frisian was the West Germanic language spoken between the 8th and 16th centuries by the people who had settled in the area between the Rhine and Elbe on the European North Sea coast in the 4th and 5th centuries. Their ancient homes were originally North Germany and Denmark. The language of the earlier inhabitants of the region (the Frisians famously mentioned by Tacitus) is not attested. Old Frisian evolved into Middle Frisian spoken from the 16th to the 19th century.
See more at Wikipedia.org...

Noun
1. the Frisian language until the 16th century; the Germanic language of ancient Frisia
(hypernym) Frisian