Pompey and the Senate's army had left Italy for Greece in 49 BC. Caesar, for lack of a fleet, solidified his control over the western Mediterranean - Spain and North Africa, specifically, before assembling ships to follow Pompey.
An indecisive winter (49/48) of blockade and siege followed. Pompey eventually pushed Caesar into Thessaly and at Pharsalus attacked. Caesar, though with a smaller army, prevailed. Pompey fled from Pharsalus to Egypt, where he was assassinated on the order of Pharaoh Ptolemy XIV Dionysus.