Pepin of Landen
The "Chronicle of Fredegar" names an earlier "Carloman" as the father of Pepin of Landen, and thus the great-great-grandfather of the Charles Martel. This would place the name "Carloman" in the 6th century, and open the possibility that the Frankish name "Carl" may originate as a short form of "Carloman". The only other compound name with the "Carl-" prefix is "Carlofred" ("Carlefred"), attested in the 7th century; as a suffix, it occurs in the rare names "Altcarl" and "Gundecarl" (9th and 11th centuries, respectively).