Who are the famous words "Alea iacta est" assigned to?

Alea iacta est ("The die is cast") is a variation of a Latin phrase (iacta alea est [ˈjakta ˈaːlea est]) attributed by Suetonius to Julius Caesar on January 10, 49 B.C. as he led his army across the Rubicon river in Northern Italy. With this step, he entered Italy at the head of his army in defiance of the Senate and began his long civil war against Pompey and the Optimates.