The great general was now ready for action. He built a line of strongly fortified forts around Pompey's camp, blockading him by land. He turned the streams of water aside, causing as much inconvenience as possible to the enemy. So the siege dragged on into June.
Two deserters informed Pompey of a weak spot in Caesar's line. At this point Pompey made a sudden attack. For once Caesar's troops were surprised and panic-stricken. Even his own presence did not cause them to rally. Nearly one thousand of his men fell, thirty-two standards, and a few hundred soldiers were captured.
This victory was the ruin of Pompey's cause. Its importance was exaggerated. His followers were sure that the war was practically over; and so certain were they of ultimate success that they neglected to follow up the advantage gained, and gave Caesar opportunity to recover from the blow.
The latter now retired from the sea-board into Thessaly. Pompey followed, confident of victory. The nobles in his camp amused themselves with quarrelling about the expected spoils of war. Cato and Cicero remained behind in Epirus, the former disgusted at the actions of the degenerate nobility, the latter pleading ill health.
The two armies encamped on a plain in Thessaly near the river Enipeus, only four miles apart. Between them lay a low hill called PHARSÁLUS, which gave name to the battle which followed.
"The battle of PHARSALIA (August 9, 48) has acquired a special place in history, because it was fought by the Roman aristocracy in their own persons in defence of their own supremacy. Senators and the sons of Senators, the heirs of the names and fortunes of the ancient Roman families, the leaders of society in Roman salons, and the chiefs of the political party of the optimates (aristocracy) were here present on the field. The other great actions were fought by the ignoble multitude whose deaths were of less significance. The plains of Pharsalia were watered by the precious blood of the elect of the earth."
For several days the armies watched each other without decisive action. One morning towards the end of May (August 9, old style) Caesar noticed a movement in Pompey's lines that told him the expected attack was coming.