plebeian. Members of it are mentioned in Roman history only during the last three centuries before the Christian era. It seems to have been of Sabine origin, and may have been connected with the Flavii that occur at Reate in the first century after Christ, and to whom the emperor Vespasian belonged. But the name Flavius occurs also in other countries of Italy, as Etruria and Lucania. During the later period of the Roman empire, the name Flavius descended from one emperor to another, Constantius, the father of Constantine the Great, being the first in the series. The cognomens that occur in the Flavia gens during the republic are FIMBRIA, GALLUS, LUCANUS, and PUSIO.
[L.S]A Dictionary of Greek and Roman biography and mythology
Smith, William
A Dictionary of Greek and Roman biography and mythology. William Smith, LLD, ed. 1890