Which Roman general conquered Gaul before crossing the Rubicon in 49 BCE?

Julius Caesar conquered Gaul before crossing the Rubicon in 49 BCE.

Caesar served as governor of Cisalpine Gaul and later Transalpine Gaul, using those commands to conduct the Gallic Wars from 58 to 50 BCE. His campaigns expanded Roman control across much of modern France and Belgium and reached into parts of Germany and Britain. He described the wars in his work Commentarii de Bello Gallico.

After his command ended, the Senate ordered him to disband his army. Caesar instead crossed the Rubicon, a boundary near Italy, in 49 BCE. This act began the civil war against Pompey and his supporters.

The famous phrase “the die is cast” is traditionally associated with the crossing. Caesar’s victory led to his dictatorship, but he was assassinated in Rome on the Ides of March in 44 BCE.