Siege of Alexandria (47 BC)

The Siege of Alexandria was a series of skirmishes and battles occurring between the forces of Julius Caesar, Cleopatra VII, Arsinoe IV, and Ptolemy XIII, between 48 and 47 BC. During this time Caesar was engaged in the Civil War between himself and the forces of the Senate.

Prelude
After the Battle of Pharsalus between the forces of Caesar and those of Gnaeus Pompey Magnus and the Senate the majority of the forces commanded by Pompey were scattered or surrendered to Caesar. Pompey however escaped via Amphipolis to Egypt. Pompey was killed upon landing in Egypt by Achillas and Lucius Septimius, former soldiers in his army. The assassination was carried out by the eunuch Pothinus and Theodotus of Chios,  advisors of the Pharaoh Ptolemy who deemed that they could endear themselves to Caesar by removing his enemy Pompey.

Events
Caesar was horrified at the murder of Pompey, and wept for his one-time ally and son-in-law. He demanded the money Ptolemy's father Ptolemy XII Auletes had been lent by Rome and agreed to settle the dispute between Ptolemy and his sister and co-regent Cleopatra VII. Caesar chose to favor Cleopatra over her brother.

Achillas subsequently joined Pothinus in resisting Caesar, and having had the command of the whole army entrusted to him by Pothinus, he marched against Alexandria with 20,000 on foot and 2,000 cavalry. Caesar, who was at Alexandria, did not have sufficient forces to oppose him, and sent ambassadors to negotiate with him. However, Achillas murdered the ambassadors to remove all hopes of reconciliation. He then marched into Alexandria and occupied most of the city. Meanwhile, Arsinoe, the younger sister of Ptolemy, escaped from Caesar and joined Achillas. In 47 BC, dissension broke out between them, and Arsinoe had Achillas put to death by Ganymedes, a eunuch to whom she then entrusted the command of the forces. Ganymedes initially enjoyed some success against Caesar, who had only the soldiers he had brought with him and a minor Italian militia left over from previous issues in 55 BC, but the leading Egyptian officers were soon dissatisfied with the eunuch. Under a pretext of wanting peace, they negotiated with Caesar to exchange Arsinoë for Ptolemy XIII, who was subsequently released only to continue the war. Relief for the Romans came in the form of Mithridates of Pergamum and Antipater from Judea. A final pitched battle was fought on the west side of the Nile River with Caesar victorious and Ptolemy drowning while attempting to cross the river.

Aftermath
Ptolemy's crown was passed to his younger brother Ptolemy XIV and Cleopatra as co-rulers. Caesar reportedly toured Egypt for two months with Cleopatra before renewing his activities in the civil war. Arsinoe was marched through Rome as a prisoner, banished to the Temple of Artemis in Ephesus, and later executed on the orders of Cleopatra and Mark Antony.