Battle of Pharsalus

The Battle of Pharsalus (9 August 48 BC) was the decisive battle of Caesar's Civil War. After crossing the Rubicon and taking Italy in a lightning campaign, Caesar failed to trap Pompey at Brundisium and spent 49 BC securing Spain before crossing to Greece, where a botched landing and a failed siege at Dyrrhachium left him short of supplies and seemingly cornered. Pompey, commanding the Senate's cause with a larger army and near-command of the sea, chose battle on the plain of Pharsalus in Thessaly. Ancient figures for his army range up to 45,000 infantry against Caesar's roughly 22,000, with several thousand cavalry on the Pompeian wing. Pompey's plan turned on a mass cavalry charge against Caesar's exposed right flank. Caesar met it by thinning his third line into a fourth, held back as a reserve with orders to strike at the horsemen's faces rather than loot the enemy camp. The charge stalled, the reserve drove it off, and the Pompeian left collapsed; legions already wavering from earlier losses broke. Pompey fled, reached Egypt, and was murdered on landing days later, leaving Caesar to report to Rome a victory that settled nothing on paper but destroyed the Republic's last united army. The battle made Caesar master of the Roman world and opened his campaigns in Egypt, Pontus, Africa, and Spain.