In 58 BC, Pharaoh Ptolemy XII "Auletes" had to leave Egypt and went into political exile in Rome due to a popular revolt, and his daughter Berenice IV seized the throne.
Schäfer believes that Cleopatra's break with the Gabiniani was the main cause of her subsequent loss of power because her actions led to the mercenaries joining those who supported Ptolemy XIII and his three influential guardians and advisors, Pothinus, Achillas, and Theodotus of Chios.
[3] In the spring of 49 BC Gnaeus Pompeius, the oldest son of the triumvir, Pompey, came to Egypt to ask for military aid in the civil war against Julius Caesar that had just broken out.
[5] After Pompey's decisive defeat in the Battle of Pharsalus, he fled to the coast of Egypt and demanded help and support from the Ptolemaic government.
The advisors of Ptolemy XIII were not willing to get involved in the Roman civil war and decided to murder Pompey in an attempt to please the victorious Caesar.
Pothinus and his companions allegedly also feared that Pompey would try to incite the former Roman soldiers in the Ptolemaic army – who had earlier fought under his command – so that he could gain control over Egypt.
Indeed two leading members of the Gabiniani, the former tribune Lucius Septimius and the centurion Salvius, participated in the assassination of Pompey (25 July 48 BC according to the Julian calendar).
Caesar relates in his Commentarii de Bello Civili that fugitive criminals and exiles from the neighbouring Roman provinces had joined the Gabiniani because the government recruited them to swell the ranks of their army.