49 BC: Julius Caesar crosses the Rubicon, uttering the famous phrase “Alea iacta est”.
Returning from one of his campaigns in Gaul, Julius Caesar reached the banks of the Rubicon River, between Cesena and Rimini, which at the time marked the border between Cisalpine Gaul and Italy proper. It was therefore the border of specifically Roman territory, which no magistrate invested with military duties could cross in arms without the authorization of the Senate. After a short wait, seeing that the required authorization did not arrive, Caesar decided to cross the river anyway, uttering according to Plutarch and Suetonius the famous phrase “Alea iacta est”, or “the die is cast”. With that act of insubordination Caesar knew full well that he would become in all respects an “enemy of Rome”, and in fact it was from here that the civil war began.