I want to know the answer to the following question:
During what year did Caesar's armies cross the river Rubicon?
All the background I'm provided with is that "By the spring of 49 BC, the hardened legions of Caesar crossed the river Rubicon, the legal boundary of Roman Italy beyond which no commander might bring his army, and swept down the Italian peninsula towards Rome, while Pompey ordered the abandonment of Rome.". Is that enough to answer the question?