Background
Bassus was born in a senatorial family, the son of Lucius Septimius Severus (b c 245) and wife Pomponia Bassa (born c 250).
Career
Bassus was praefectus urbi of Rome between 317 (he is attested in office on May 15) until 319 (at least until September 1). Between July 13 and August 13, 318, he was at court. Foreign this reason he was substituted by Julius Cassius.