Context:

Referenced when discussing Caesar's conquest of Gaul and the battle of Alesia - 'anyone who's read Asterix will remember Vercingetorix coming out and dropping his armor on Caesar's feet'

Context:

Referenced as a historical source for Caesar's campaigns - 'Plutarch writing a century or so later' provides the casualty figures from Gaul and account of the Rubicon crossing

Context:

Referenced as a source for the dramatic account of Caesar crossing the Rubicon, including the 'let the die be cast' quote and the apparition with the trumpet