Commentarii de Bello Gallico
Early literature such as Julius Caesar's "Commentarii de Bello Gallico" or Xenophon's "Anabasis", both ostensibly non-fictional accounts of wars led by their authors, used illeism to impart an air of objective impartiality, which included justifications of the author's actions. In this way personal bias is presented, albeit dishonestly, as objectivity.