Which historian wrote “The Twelve Caesars,” a major ancient source on Julius Caesar? The answer is Suetonius.
Gaius Suetonius Tranquillus wrote De vita Caesarum, usually called The Twelve Caesars, in Latin during the early second century AD. The work presents biographies of Julius Caesar and the first 11 Roman emperors, ending with Domitian. Although Caesar was not technically an emperor, Suetonius begins the collection with him because he founded the dynasty and political tradition later associated with the Caesars.
Suetonius was a Roman biographer and administrative official who served under the emperors Trajan and Hadrian. His biographies combine political events with family history, physical descriptions, sayings, habits, omens, scandals, and anecdotes. That personal focus makes the work vivid, but it also means historians treat some stories cautiously because Suetonius sometimes relied on rumor or hearsay.
A common mix-up is Tacitus, another major Roman historian who wrote the Annals and Histories. Tacitus is indispensable for imperial history, but The Twelve Caesars is specifically Suetonius’s work. Its account of Caesar is one of several important ancient perspectives, alongside Caesar’s own writings and Plutarch’s Life of Caesar.