When Caesar returned to Rome after ten years away with his legion after defeating all of Rome’s enemies, he came to the Rubicon.
Crossing the Rubicon River would have been a natural thing for Caesar to do by himself to enter Rome. He wanted to take his legion into Rome, to share the wagonsfilled with gold he brought back with themembers of the Senate.
Crossing the Rubicon with the legion was not allowed by Roman law – that’s how Roman democracy worked for centuries.
The legion couldn’t enter Rome without the consent of the Senate.
The generals couldn’t run Roman society. The Roman Senate did that.
Caesar on his horse by the Rubicon shouted to his legion: “Jacta est alia”. The die is cast, is what he said ( and he said it in Greek, the ancient language of record during Roman times).
The legion led by Caesar crossed the river and went into the city.
Thus ended Roman democracy.