the die is cast
The form “the die is cast” is from the Latin iacta ālea est
Prov. A process is past the point of no return. (The die is one of a pair of dice. The cast means thrown.
This phrase [in Latin] was said by Julius Caesar when he crossed the Rubicon with his legions, starting a civil war.)
From games of chance in which the outcome is determined by the throwing of dice or a single die.
\Popularized by its use by Suetonius when Julius Caesar crossed the Rubicon to begin a civil war in the Roman Republic, indicating the commission of an irreversible act, whence also cross the Rubicon.
The form “the die is cast” is from the Latin iacta ālea est, a grammatically incorrect translation by Suetonius, 121 CE, of the Ancient Greek phrase of Menander ἀνερρίφθω κύβος (anerrhíphthō kúbos), which Caesar quoted in Greek (not Latin). The Greek translates rather as “let the die be cast!”, or “let the game be ventured!”.