How did Caesar defeat Pompey’s larger army at Pharsalus?

At the Battle of Pharsalus in 48 BCE, Julius Caesar overcame Pompey the Great’s larger, less disciplined force through superior tactics and the experience of his veteran legions.1

While Pompey held a significant advantage in cavalry, Caesar anticipated a flanking maneuver by Pompey’s commander, Titus Labienus. To counter this, Caesar concealed a fourth line of six to eight cohorts behind his own cavalry on his right flank. When Labienus charged, Caesar’s hidden cohorts surprised the loyalist cavalry, forcing them to flee into the hills.

With the cavalry routed, these cohorts attacked the exposed left flank of Pompey’s infantry. Simultaneously, Caesar committed his third line of reserves to the main engagement, which pressured the loyalist center and caused the lines to break. Pompey’s army, composed largely of inexperienced levies, collapsed under this coordinated assault, leading to a decisive victory for Caesar.1