“What then is, generally speaking, the truth of history? A fable agreed upon.”
Napoleon I of France (1769–1821) French general, First Consul and later Emperor of the French
Conversation with Emmanuel, comte de Las Cases (20 November 1816), Mémorial de Sainte Hélène, v. 4, p. 251 http://books.google.com/books?id=945jAAAAMAAJ&vq=%22fable%20agreed%20upon%22&pg=PA251. However, the phrase predates Napoleon. Helvétius attributes it to Bernard le Bovier de Fontenelle, De l'esprit (1758), p. 443 http://books.google.com/books?id=N7g8AAAAcAAJ&vq=%22fable%20convenue%22&pg=RA1-PA443