Regum et imperatorum apophthegmata

Plutarch

Plutarch. Moralia, Vol. III. Babbitt, Frank Cole, translator. Cambridge, MA: Harvard University Press; London: William Heinemann Ltd., 1931 (printing).

And he crossed the river Rubicon from his province in Gaul against Pompey, saying before all, Let the die be cast. [*](Ibid. chap. xxxii. (723 F); Life of Pompey, chap. lx. (651 D); Suetonius, Divus Iulius, 32 iacta alea est or esto. The expression seems to have been proverbial; Cf. Leutsch and Schneidewin, Paroemiographi Graeci, i. p. 383 and the references; Aristophanes, Frag. 673 Kock, Com. Att. Frag. i. p. 557 and Menander, Frag. 65, Ibid. iii. p. 22.)