Battle of Pharsalia

Battle of Pharsalus
Part of Caesar's Civil War
Date 9 August 48 BC Location Palaeopharsalos (Greece) Result Decisive Caesarian victory
Belligerents
Forces of Julius Caesar, including representatives of the Populares	Forces of Pompey, including many of the Optimates
Commanders and leaders
Gaius Julius Caesar Mark Antony	Gnaeus Pompeius Magnus
Strength
Approximately 22,000 legionaries (elements of 9 legions), 5,000–10,000 auxiliaries and allies, and allied cavalry of 1,800	Approximately 40,000–45,000 legionaries (12 legions), 4,200 auxiliaries and allies, and allied cavalry of 5,000–8,000
Casualties and losses
~230 (according to Caesar)	6,000–15,000

The Battle of Pharsalus was a decisive battle of Caesar's Civil War. On 9 August 48 BC at Pharsalus in central Greece, Gaius Julius Caesar and his allies formed up opposite the army of the republic under the command of Gnaeus Pompeius Magnus ("Pompey the Great"). Pompey had the backing of a majority of the senators, of whom many were optimates, and his army significantly outnumbered the veteran Caesarian legions.

The two armies confronted each other over several months of uncertainty, Caesar being in a much weaker position than Pompey. The former found himself isolated in a hostile country with only 22,000 men and short of provisions, while on the other side of the river he was faced by Pompey with an army about twice as large in number. Pompey wanted to delay, knowing the enemy would eventually surrender from hunger and exhaustion. Pressured by the senators present and by his officers, he reluctantly engaged in battle and suffered an overwhelming defeat, ultimately fleeing the camp and his men, disguised as an ordinary citizen.

A dispute between Caesar and the optimates faction in the Senate of Rome culminated in Caesar marching his army on Rome and forcing Pompey, accompanied by much of the Roman Senate, to flee in 49 BC from Italy to Greece, where he could better conscript an army to face his former ally. Caesar, lacking a fleet to immediately give chase, solidified his control over the western Mediterranean – Spain specifically – before assembling ships to follow Pompey. Marcus Calpurnius Bibulus, whom Pompey had appointed to command his 600-ship fleet, set up a massive blockade to prevent Caesar from crossing to Greece and to prevent any aid to Italy. Caesar, defying convention, chose to cross the Adriatic during the winter, with only half his fleet at a time. This move surprised Bibulus, and the first wave of ships managed to run the blockade easily. Now prepared, Bibulus managed to prevent any further ships from crossing, but died soon afterwards.

Caesar was now in a precarious position, holding a beachhead at Epirus with only half his army, no ability to supply his troops by sea, and limited local support, as the Greek cities were mostly loyal to Pompey. Caesar's only choice was to fortify his position, forage what supplies he could, and wait on his remaining army to attempt another crossing. Pompey by now had a massive international army; however, his troops were mostly untested raw recruits, while Caesar's troops were hardened veterans. Realizing Caesar's difficulty in keeping his troops supplied, Pompey decided to simply mirror Caesar's forces and let hunger do the fighting for him. Caesar began to despair and used every channel he could think of to pursue peace with Pompey. When this was rebuffed he made an attempt to cross back to Italy to collect his missing troops, but was turned back by a storm. Finally, Mark Antony rallied the remaining forces in Italy, fought through the blockade and made the crossing, reinforcing Caesar's forces in both men and spirit. Now at full strength, Caesar felt confident to take the fight to Pompey.

...
Wikipedia