The river Rubicon; “Alea iacta est“
During the Roman republic, the river Rubicon marked the boundary between the Roman province of Cisalpine Gaul to the north-east and Italy proper to the south. Governors of Roman provinces were appointed promagistrates with imperium (roughly, “right to command”) in their province(s). The governor would then serve as the general of the Roman army within the territory of his province(s). Roman law specified that only the elected magistrates (consuls and praetors) could hold imperium within Italy. Any promagistrate who entered Italy at the head of his troops forfeited his imperium and was therefore no longer legally allowed to command troops. Exercising imperium when forbidden by the law was a capital offence. Furthermore, obeying the commands of a general who did not legally possess imperium was also a capital offence. If a general entered Italy whilst exercising command of an army, both the general and his soldiers became outlaws and were automatically condemned to death. Generals were thus obliged to disband their armies before entering Italy.
So when Julius Caesar
on January 10, 49 BC uttered the famous words, “Alea iacta est“ or “The die is cast” as he led his army across the River Rubicon in Northern
Italy, he was very much aware of what would happen, as were his enemies, his
soldiers, friends and family.