Near Dyrrahachium, a town on the eastern coast of the Adriatic Sea, the Roman Civil War came to a head as the army of the Optimates (the majority of the Senate) under Pompey the Great clashed with the forces of the Populares (the party of the people) under Julius Caesar. Caesar had landed earlier with split troops and now regrouped with his legate Marc Antony with Pompey maneuvering from between them. With 15,000 men and 500 cavalry, Caesar quickly began building forts while Pompey held his fortified positions with 45,000 men.
With Caesar captured, Pompey and the Senate were victorious. Some senators called for Caesar to be dragged back to Rome in chains for execution, but Pompey refused. He Caesar was honorable, if ambitious, and he was given full rights as a Roman citizen, even excused of potential treason. The senatorial army retook Rome and Caesar's trial began while Pompey carried out the long process of calming Caesar's allies in Gaul and Spain. Three times over the course of Caesar's trial, Pompey would return to Rome with soldiers (both his own and former ones of Caesar's) to quell propositions for overly violent propositions by the Senate.
The trial was a desperate balancing act. On the one hand, Optimates called for Caesar's blood at beginning the civil war. On the other, the people of Rome still held grand esteem for the fallen warlord. Caesar himself, a brilliant orator, could set the city aflame with mere words or letters from his house arrest. Some suggested a quiet assassination, but Pompey and others vetoed the notion. Caesar's death would no doubt begin a second civil war.
At last Caesar was reprimanded for his military activities being impertinent toward Rome and the gods. After many fines and being stripped of most of his titles, Caesar was broken but hardly defeated enough for his many allies to call for retribution. Pompey suggested (or, it is believed, acted as the conduit for a suggestion of Caesar's, as the two remained friends despite their political differences) sending Caesar to the east to settle the frontier there while in exile.
Within a few short years, Caesar would regain his prowess. He would settle the question of Egyptian succession, overturning the attempted coup by Ptolemy XIII and securing Cleopatra VII (who famously became Caesar's lover) to the throne. With his armies still active, Caesar would move across Sinai to quell the Judaeans and even give spark to a fire that would end the Persian Empire, long rivals to the Romans. Using factions against one another as he did in Gaul, Caesar conquered Mesopotamia and marched to the Indus, procuring alliances with princes there.
Caesar's enemies in the Senate once again called for his return to face charges of war crimes (namely, again using his troops more than was legally required or allowed). Pompey would do his best to see that Caesar remained out of the eyes of the people, lest his ambition cause another war, but with Caesar's allies and enemies alike shouting for his recall, Caesar soon came home to Rome, again bringing his most loyal veterans with him. The resulting conflict would cause Caesar to again be named dictator in Rome, a position his adopted sons Marc Antony and grand-nephew Octavian carry on after Caesar's death, establishing a revolution that would carry the Roman Republic peaceably until it grew inflated, rich, and fat, ready for plucking by German barbarians in the fourth century.
In reality, Pompey ordered a halt after the rout of Caesar's troops, often attributed to Pompey's growing fearful or weak with age. Caesar's troops regrouped, resupplied, and rested at Gomphi, readying for the Battle of Pharsalus, where Caesar would soundly defeat Pompey's troops. Pompey would flee to Egypt, where Caesar would pursue him, only to find him assassinated. Caesar's rage at the murder of his friend, a Consul of Rome, and widower of his only (legitimate) daughter prompted him to overthrow Ptolemy to secure punishment for all involved in the slaying.