the die is cast
From games of chance in which the outcome is determined by the throwing of dice or a single die. Popularized by its use by Julius Caesar when he crossed the Rubicon to begin a civil war in the Roman Republic, indicating the commission of an irreversible act, from whence also cross the Rubicon.
The form “the die is cast” is from the Latin iacta alea est, a mistranslation by Suetonius, 121 CE, of the Ancient Greek phrase of Menander «Ἀνερρίφθω κύβος» (anerriphtho kybos), which Caesar quoted in Greek (not Latin). The Greek translates rather as “let the die be cast!”, or “Let the game be ventured!”, which would instead translate in Latin as iacta alea esto.
- Caesar: ... "Iacta alea est", inquit.
- Caesar said ... "the die is cast".
- Ἑλληνιστὶ πρὸς τοὺς παρόντας ἐκβοήσας, «Ἀνερρίφθω κύβος», [anerriphtho kybos] διεβίβαζε τὸν στρατόν.
- He [Caesar] declared in Greek with loud voice to those who were present ‘Let the die be cast’ and led the army across.
Suetonius’s much-quoted and much-translated translation of the Greek (as reported by Plutarch) is apparently incorrect – according to Lewis and Short, the phrase used was a future active imperative, “let the die be cast!”, or “Let the game be ventured!”, which would instead translate in Latin as iacta alea esto.
- (idiomatic) The future is determined; there are no more options; events will proceed in an irreversible manner; the point of no return has been passed.
Coordinate terms 
See also 
- ^ Vita Divi Iuli (The Life of the deified Julius), 121 CE, paragraph 33 (Caesar: ... "Iacta alea est", inquit. – Caesar said ... "the die is cast".)
- ^ Plutarch, Life of Pompey, 60.2.9. See also Plutarch's Life of Caesar 32.8.4 and Sayings of Kings & Emperors 206c.
- ^ Online Dictionary: alea, Lewis and Short at the Perseus Project. See bottom of section I.