Cæsar halted for a time, while messages about this went to and fro between him and the Senate, the Senate ordering him to disband the troops, and Cæsar refusing. He halted on the banks of a small stream, the Rubicon, which has become very famous because it was the boundary of Italy beyond which he was forbidden to go at the head of troops.
Finally, in the year 49 B.C., he determined to go against the order of the Senate and brave the consequences. Cæsar crossed the Rubicon!
The crossing of that river meant war. Cæsar knew it. The Senate knew it. Pompey knew it. The great Pompey fled before him, and took command of the Senatorial armies in Greece. Cæsar, who had no fleet, went in pursuit.
They met at Pharsalia, in Thessaly, and there was fought one of the great battles of history. Cæsar gained the day, and Pompey again fled, into Egypt. Again Cæsar pursued him, and was met on coming to Egypt by a messenger who thought to find favour with him by bringing him the head of Pompey, who had been murdered. But Cæsar was a generous enemy. Pompey had been his friend, and he mourned his death with respect.
Cleopatra
There was trouble in Egypt at this time. The rulers were supposed to be one of the Ptolemies and Cleopatra, also of the same family, the two sharing the throne. But the Ptolemy had thrust the queen out and claimed to rule alone. Cæsar, captivated by the beauty of Cleopatra, restored her to her share in the government. Then he marched up with his force into Syria. There, too, there was trouble.
The trouble was with a powerful people called the Parthians, coming from that part of Asia, east of the Euphrates, from which the Persians had come long ago. They were a warlike nation, fighting on horseback, lightly clad in mail; and their mode of fighting was like that of the Persians of old—to come galloping down upon the enemy, to shower arrows, discharged from horseback, upon him, to gallop off again, turning in the saddle and shooting as they went, and then to reform, to come back again, and repeat the same tactics until the enemy's formation was broken up.
Really it was very like the fighting of the Persians, which, as we saw, was broken by the solid Greek phalanx. But these Parthians prevailed in several battles against the Roman legions. They had defeated a Roman army under the command of that Crassus who was one of the triumvirate. Of these three, Cæsar was the only one who was alive after Pompey's murder in Egypt.
Cæsar met the Parthian forces and defeated them very heavily. He drove them back over the Euphrates; and the Euphrates we have to look on as the boundary, eastward, of the Roman power. The Romans did not try to press farther. They had enough, and more than enough, work on their hands in making good the conquests they had gained.
Cæsar returned to Rome, victorious; but still he had enemies, in the shape of armies in the field, under commanders appointed by the Senate. There were some such forces in Africa. Thither Cæsar went and made an end of them. Still there were others in Spain, and there, at length, he seems to have put out the last spark of opposition by a victory in the battle of Munda in 45 B.C. He had crossed the Rubicon in 49 B.C. What he had accomplished in those four years is wonderful. Victorious in Greece, Egypt, Syria, Africa, Spain. All enemies had gone down before him. He was elected "dictator for life" of the Roman Commonwealth.