However, by the spring of 48 BC Cleopatra traveled to Syria with her younger sister Arsinoe IV to gather an invasion force that would head to Egypt. She returned with an army, perhaps right around the time of Caesar's arrival, but her brother's forces, including some Gabiniani mobilized to fight against her. They blocked her advance to Alexandria, and she had to make camp outside Pelousion in the eastern Nile Delta. In Greece, Caesar and Pompey's forces engaged each other at the decisive Battle of Pharsalus on 9 August 48 BC, leading to the destruction of most of Pompey's army and his forced flight to Tyre, Lebanon. Given his close relationship with the Ptolemies, he ultimately decided that Egypt would be his place of refuge, where he could replenish his forces. Ptolemy XIII's advisers, however, feared the idea of Pompey using Egypt as his base of power in a protracted Roman civil war. They also wanted to ensure that none of the Gabiniani would leave their campaign against Cleopatra to join Pompey's forces instead. In a scheme devised by Theodotos, Pompey arrived by ship near Pelousion after being invited by written message, only to be ambushed and stabbed to death on 28 September 48 BC. Ptolemy XIII believed he had demonstrated his power and simultaneously defused the situation by having Pompey's severed head sent to Caesar, who arrived in Alexandria by early October and resided at the royal palace. Theodotos presented Caesar with his son-in-law Pompey's embalmed head, which Caesar retrieved and planned to bury properly along the shores of Alexandria. Caesar expressed grief and outrage over the killing of Pompey, and called on both Ptolemy XIII and Cleopatra VII to disband their forces and reconcile. Caesar's request for partial repayment of the 17.5 million drachmas owed to Rome (to pay for immediate military expenditures) was met with a response by Potheinos. He replied that it would be made later if Caesar would leave Alexandria, but this offer was rejected. Ptolemy XIII arrived at Alexandria at the head of his army, in clear defiance of Caesar's demand that he disband and leave his army before his arrival. Cleopatra initially sent emissaries to Caesar, but upon allegedly hearing that Caesar was inclined to having affairs with royal women, she came to Alexandria to see him personally. Historian Cassius Dio records that she simply did so without informing her brother, dressing in an attractive manner and charming Caesar with her wit and linguistic skills.