The battle of Pharsalus took place in Thessaly, near the city of the same name, on August 9, 48 BC, during the Roman civil war which closed the Republic. Here Caesar gained a decisive advantage over Pompey, his troops and the Senate.
Caesar camped north of the Enipeus River in Thessaly. Pompey's camp is 5 kilometers to the northwest. After long maneuvers to take the best positions, the two armies end up lining up in line of battle.
Thanks to his superiority in cavalry, Pompey wants to take Caesar's right wing from the flank. Indeed, the tenth legion, Caesar's favorite with which he is used to fighting, is at this location. To decimate this legion would be a feat for Pompey. Caesar counters by reinforcing his cavalry with 8 cohorts. He gives the order to these reinforcements to hit Pompey's cavalry in the face, which will come to the charge. This is to scare the riders, who are mostly young mercenaries who don't want to be disfigured.
The two armies are closing in. Arrived within range of the charge, Pompey does not order the charge, he hopes that Caesar's soldiers who will have to charge over a double distance will arrive exhausted on his troops. But Caesar's veterans fan the trap and stop halfway to reorganize. The battle lines come into contact, the fight is equal, neither the troops of Caesar nor that of Pompey manage to break the opposing line. Pompey's cavalry pushes back Caesar's, but the 8 support cohorts placed by Caesar charge and disperse Pompey's cavalry. Caesar's cavalry pursues Pompey's cavalry, and the supporting cohorts attack the left flank of Pompey's army from the rear.
Virtually surrounded, Pompey's army was destroyed on the spot.
Pompey flees to Egypt where he will be assassinated, while Metellus Scipio and Cato leave for Africa to recreate an army. Cicero, who had not taken part in the fighting surrenders to Caesar, as well as Brutus.
Caesar must continue his fight in Africa.