Still determined to depose Cleopatra VII, Ptolemy XIII allied himself with Arsinoe IV. Jointly, they organized the factions of the army loyal to them against those loyal to Cleopatra VII and the relatively small part of his army that had accompanied Caesar to Egypt. The battle between the warring factions occurred in mid-December 48 BC inside Alexandria itself (Siege of Alexandria (47 BC)), which suffered serious damage. Around this time, the burning of the Library of Alexandria occurred.