Caesar's advance down the Adriatic coast was surprisingly clement and disciplined: his soldiers did not plunder the countryside as soldiers had during the Social War a few decades earlier; Caesar did not avenge himself on his political enemies as Sulla and Marius had done. The policy of clemency was also highly practical: Caesar's pacificity prevented the population of Italy from turning on him. At the same time, Pompey planned to escape east to Greece where he could raise a massive army from the eastern provinces. He therefore escaped to Brundisium (modern Brindisi), requisitioning merchant vessels to travel the Adriatic.

Julius Caesar's besieges the Italian city of Brundisium on the coast of the Adriatic Sea which was held by a force of Optimates under the command of Gnaeus Pompeius Magnus. After a series of brief skirmishes, during which Caesar tried to blockade the harbour, Pompey abandoned the city and managed to evacuate his men across the Adriatic to Epirus. Pompey's retreat meant that Caesar had full control over the Italian Peninsula, with no way to pursue Pompey's forces in the east he instead decided to head west to confront the legions Pompey had stationed in Hispania.

On his way to Hispania, Caesar took the opportunity to return to Rome for the first time in nine years. He wished to appear as though he was the legitimate representative of the Republic and so he arranged for the Senate to meet with him outside the boundaries of the city on 1 April. Also invited was the great orator Cicero to whom Caesar sent letters imploring him to come to Rome, but Cicero was not to be persuaded as he was determined not to be used and was wary of the increasingly ominous tone of the letters.