Suetonius (Caius Suetonius Tranquillus), c.A.D. 69-c.A.D. 140, Roman biographer. Little is known about his life except that he was briefly the private secretary of Emperor Hadrian. His De vita Caesarum [concerning the lives of the Caesars] survives almost in full; it was translated into English by Robert Graves as The Twelve Caesars (1957). There are also fragments of a much larger collection of biographies, De viris illustribus [concerning illustrious men]. He gathered together all sorts of anecdotes, and the resultant biographies are lively and informative. Suetonius was taken as a model by many later biographers.