This expression means an irrevocable choice has been made; if somebody had been thrown the die, the result could not be changed any more, as in a gamble. The die referred to, was the singular form of a pair of dice. Julius Caesar is supposed to have spoken this phrase when crossing the Rubicon despite the Roman law that forbade any general from crossing that river and entering Italy with an army. The earliest English citation of the saying is from 1634.

Übersetzung:

die Würfel sind gefallen

Gegenteil(e)

The opposite of "the die has been cast" is "it's all up in the air".

Synonym(e):

You could also say: to reach a point of no return.