Now by 53 BC the first Triumvirate had broken up, and with one of the members dead, it seemed pretty unlikely they were getting back together for a ten year comeback. Caesar decided to take his act on the road, got as far as Britain before the legion broke down with a flat tire, ate one too many helpings of mushy peas, and marched back to Gaul where they at least knew how to cook. Meanwhile, rioting in Rome caused Pompey to be elected as sole consul, or “Consul without a Colleague.” This was a big departure from the two consul rule developed back in the second post, and some people were afraid all the power would go to Pompey’s head. Other people figured it already had, but since they wanted to be on the winning team, they got behind Pompey and formed a group called the Optimates.
Caesar was none too happy about loss of Consulship (even though he got bored with it in the first place), so he decided to make himself the governor of Gaul. He was surprisingly effective at administration and still found time to write a book, the Gallic Wars. This irked the Optimates back in Rome since they had no free time whatsoever, so they tried to end his governorship while declaring if he came back to Rome he would be prosecuted. (Somehow they failed to see how these aims could be contradictory.)
Neither Caesar nor Pompey were willing to back down, so they went whole hog and declared another civil war. In 49 BC, Caesar decided it was time for a grand gesture, so he led his troops across the Rubicon river, which formed the border of his territory. This was considered an act of treason. According to the historian Suetonius, before he crossed Caesar said, “ālea iacta est,” which roughly translates to, “oh fuck it.” This scared Pompey so much that he ran to Greece, completely forgetting that his legions were in Spain.
Thus Caesar was able to march on Rome, declare himself dictator, and devote the rest of his time to chasing Pompey around the globe. In a final battle at Pharsalus, Caesar defeated Pompey’s army once and for all. Pompey fled to Egypt where his head was unfortunately disconnected from his body by the Pharaoh who had heard all about it and did not want to get on Caesar’s bad side. Caesar then did the remarkably un-Roman thing of pardoning everyone involved in the battle. Included among these were Mark Antony and Brutus, and it doesn’t take a brilliant tactician to see that was not going to end well.