The far-off places of the Roman Empire were always fighting against Rome trying to get rid of her rule, and had to be kept in order by a general with an army. As Cæsar had shown such bravery in fighting the pirates he was given an army and sent to fight two of these far-off places--Spain and a country north of Spain then known as Gaul, which is now France. Cæsar conquered these countries, and then he wrote a history of his battles in Latin, which of course was his own language. Nowadays this book, called “Cæsar’s Commentaries,” is usually the first book which those who study Latin read. In 55 B. C. Cæsar crossed over in ships to the island of Britain, which is now England, conquered it, and went back again next year in 54 B. C. Cæsar was becoming famous for the way he conquered and ruled over the western part of the Roman Empire. Besides this, he was very popular with his soldiers. Now there was in Rome at this time another general named Pompey. Pompey had been successfully fighting in the eastern part of the Roman Empire while Cæsar had been fighting in the west. Pompey had been a great friend of Cæsar, but when he saw how much land Cæsar had conquered and how popular he was with his soldiers, he became very jealous of him. Notice how many quarrels and wars are caused simply by jealousy. You have heard of at least two already. So while Cæsar was away with his army Pompey went to the Roman Senate and persuaded the senators to order Cæsar to give up the command of his army and return to Rome. When Cæsar received the order from the Senate to give up his command and return to Rome, he thought over the matter for some time. Then at last he made up his mind that he would return to Rome, but he would _not_ give up his command. Instead, he decided that he and his army would take command of Rome itself. Now, there was a little stream called the Rubicon which separated the part of the country over which Cæsar was given charge from that of Rome. The Roman law forbade any general to cross this stream with an army ready to fight--this was the line beyond which he must not pass, for the Romans were afraid that if a general with an army got too close to Rome he might make himself king. When Cæsar decided not to obey the Senate, he crossed this stream--the Rubicon--with his army and marched on to Rome. People now speak of any dividing line from danger as “the Rubicon” and say that a person “crosses the Rubicon” when he takes a step from which there is no turning back, when he starts something difficult or dangerous which he must finish. When Pompey heard that Cæsar was coming he took to his heels and fled to Greece. In a few days Cæsar had made himself head not only of Rome but of all Italy. Cæsar then went after Pompey in Greece and in a battle with his army beat him badly. Now that Pompey was out of the way, Cæsar was the chief ruler of the whole of the Roman Empire.