Crossing the Rubicon

Crossing the Rubicon is a piece of history that made its way into American popular culture --the saying describing a situation where there is no turning back.

The historical event that created the saying occurred on January 10^th, 49 BC, when Julius Caesar led a single Roman legion across the Rubicon River in Northern Italy.

The Rubicon River in Eastern Italy and the Arno River in Western Italy formed the northern boundary of Republican Italy in the 1st Century BC, separating it from Cisalpine Gaul. Roman law required that that only city magistrates from Rome lead an army south of the two rivers and Pro-consuls who had military control of the provinces were not allowed to enter with an army. Violation of this law, meant the loss of Imperium to command troops and was an act of treason.

Caesar, through his agents in the Senate, which included the Tribune Antony, tried to negotiate an accommodation with Pompey and the Senate. Caesar requested a new provincial assignment in order to retain Imperium and avoid prosecution for bribery and theft in office. The Senate was unwilling to meet his demand and circumstances began to move toward a confrontation.

A resolution was introduced on the Senate requiring that both Caesar and Pompey give up their commands as an attempt to satisfy both factions. Caesar was in favor, but a small group of Senators vetoed the resolution because they suspected a trap. The Senate then introduced a resolution proposing that two of Caesar’s legions be sent to Syria. Pompey favored this attempt to declaw Caesar and Caesar complied.

In December 50 BC a second resignation resolution was proposed in the Senate, requiring Caesar to give up his command without requiring Pompey to do so. This was later amended, requiring both men to give up their posts simultaneously. The vote was 370 for and 22 against.

This action by the Senate was immediately rendered useless when a panic followed. Rumors started that Caesar was already matching on Rome, so the Senate granted Pompey command for the defense of the city. A resolution was introduced placing a fixed date on Caesar’s resignation, but this was vetoed by Antony. Then, on January 7th 49 BC, an emergency decree was passed, legalizing Pompey’s authority and requested that all major officials move to protect the state. Antony was forced to flee Rome or suffer penalties under this martial law. The Senate’s final act in this drama was to assign new governors for Gaul, replacing Caesar.

The Senate’s behavior convinced Caesar that diplomatic efforts were no longer possible and a show of force was necessary, so he crossed the Rubicon on January 10^th. He divided his legion into two columns: one headed for Arretium and the other Ariminum.

The speed with which Caesar advanced astonished the Senate and Pompey, who were not convinced he would try to press an attack with one legion. By day three, Arretium had already fallen. Rather than resisting Caesar, the locals along his route opened their doors to him and even expelled Pompey’s garrisons from their territory. Surprised at this, Pompey retreated south to Capua, leaving Rome unprotected and forcing his allies in the Senate to abandon the city and join him.

Caesar arrived in Rome the first week of March with six legions. He had accumulated additional troops on his way south based on loyalty to his cause. There was some resistance, on the way, but little bloodshed because his enemies had melted away. Caesar impressed all with his leniency toward those who opposed him by setting them free.