Siege of Alexandria (47 BC)

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Siege of Alexandria
Part of Alexandrine Civil War
Datelate 48 BC – early or mid 47 BC
Result Roman victory
Roman Republic Ptolemaic Kingdom
Commanders and leaders
Gaius Julius Caesar
Cleopatra VII
Ptolemy XIII
Arsinoe IV (POW)

3200 infantry
800 cavalry

Elements of Legio VI and Legio XXVII

After reinforcements:
8000 infantry
800 cavalry
19 warships and 15 smaller vessels

Reinforcements: 1 full legion (Legio XXXVI)
20,000 infantry
2,000 cavalry
An unknown number of militia
27 warships
Casualties and losses
Unknown Unknown

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 a civil war against remaining republican forces.

The siege was lifted by relief forces arriving from Syria. After a battle contesting those forces' crossing of the Nile delta, Ptolemy XIII and Arsinoe's forces were defeated.



After the Battle of Pharsalus, Pompey abandoned his defeated army and fled with his advisors overseas to Mytilene and thence to Cilicia where he held a council of war.[1] Pompey's council of war decided to flee to Egypt,[2] which had in the previous year supplied him with military aid.[3]

Upon his arrival in Egypt, he was murdered by Achillas and Lucius Septimius, former soldiers in his army, under the orders of the eunuch Pothinus and Theodotus of Chios,[4][5][6] advisors of the pharaoh Ptolemy who believed Caesar would be pleased by the removal of his adversary.[7]

Caesar landed in Alexandria three days after Pompey's death with some three thousand men and eight hundred Germanic auxiliary horse, arrogantly occupying parts of the Alexandrian royal quarter.[8][9] Caesar was either horrified, or pretended to be horrified, at the murder of Pompey, and wept for his one-time ally and son-in-law. He demanded a ten million denarii payment towards a debt of Ptolemy's father, Ptolemy XII Auletes, and declared his intention to mediate the dispute between Ptolemy and his sister Cleopatra VII.[10][11]

Start of the siege

After the payment demand, Pothinus sent secret orders summoning Achillas and an army of some twenty thousand men to Alexandria, where they besieged and then launched an all-out attack on the Royal Quarter. Initial fighting was fierce, with an accidental fire spreading to the famous Library of Alexandria, though damage to the library was likely minimal.[10] During the siege, Cleopatra secreted herself into the Royal Quarter and eventually became Caesar's lover.[12] Around the time the relationship started, Caesar also declared that he viewed Ptolemy XII Auletes's will to invest both Cleopatra and Ptolemy XIII with joint rule over the kingdom.[13] Ptolemy XIII was not impressed with the decision, "probably already aware that his sister was closer to the Roman consul [Caesar] than he could ever be" and incited a Alexandrian riot against Caesar.[13]

With tensions rising in the palace compound, Caesar took to drinking with his officers well into the night; Caesar claimed this was for his own protection. After one of Caesar's slaves discovered communications between Pothinus and the besiegers, Caesar had Pothinus executed.[13]

Meanwhile, Arsinoe IV, the younger sister of Ptolemy, escaped from Caesar and joined the Egyptian army, which proclaimed her queen.[13] She arranged successfully with her eunuch tutor Ganymede the murder of Achillas and then assumed command of the army, renewing the siege. Caesar's water supplies were contaminated, forcing him to dig wells.[13] Reinforcements from his Thirty-seventh legion, a former Pompeian formation, also then arrived by sea bringing supplies and artillery.[13]

Naval battle

Soon after the siege began Caesar made a sally against the Great Harbor and burned the Alexandrian fleet, damaging the Great Library in the process. Ganymedes ordered the Alexandrians to make repairs on as many ships as possible. They were able to ready 27 warships for battle. Caesar unwilling to give up his naval superiority drew up his own fleet, 19 warships and 15 smaller vessels, in two lines just north of the coast of Pharos Island. Ganymedes sailed out from the Eunostos Harbor and formed two lines opposite Caesar's fleet. Between the two fleets were shoals, a narrow channel being the only way through. Both sides eventually held their position neither wanting to make the initial move.

Euphranor, the commander of Caesar's Rhodian allies, convinced Caesar he and his men could push through and hold for long enough to let the rest of the fleet pass through the channel. Four Rhodian ships sailed through the channel and formed a line against the Alexandrian ships rapidly closing in delaying them long enough for the rest of Caesar's fleet to pass through. With the channel to his back Caesar needed to win because retreat would be disastrous. Though the Alexandrians were excellent sailors the Romans had one deciding advantage: because of the proximity of the coast and the shoals there was little room for manoeuvre. The ships were forced into close combat something the Romans excelled at. Two Alexandrian ships were captured, three more were sunk, the rest fled back to the Eunostos.

Battle for Pharos

After winning the battle for naval supremacy Caesar turned his attention to Pharos Island. The island was crucial for controlling access into the harbors and was linked to the mainland through a bridge, the Heptastadium, connected by two moles, one from the island one from the mainland. Caesar had stationed a small garrison on the northeastern part of the island opposite the Lighthouse of Alexandria. He ordered ten cohorts of legionaries, some light infantry and his Gallic cavalry to board their transports and led them on an amphibious assault of the island while his garrison on the island attacked the Alexandrians simultaneously.

After a hard fought battle the Alexandrians retreated from the island. Caesar fortified defences around the bridge controlling access to the Pharos, the Alexandrians doing the same on the mainland. The bridge had a large arch through which the Alexandrians could send ships to attack Caesar's transports. In order to stop the Alexandrians from doing this Caesar needed to take control of the bridge. The day after taking the island he sent several ships with archers and artillery to clear the bridge and then landed himself with three cohorts on the bridge. He ordered his men to start constructing a rampart on the bridge while men from the Pharos brought up stones to block the arch. The Alexandrians suddenly launched an two-pronged counterattack by land and sea in order to take the bridge back. Caesar's captains decided to take the initiative themselves by landing archers and slingers on the bridge to fend off the enemy ships. The Alexandrians however landed their troops behind them and attacked them from the rear. Caesar's light troops were quickly outfought by the heavily armed Alexandrian soldiers. Caesar was now caught in a pincer and ordered his troops to withdraw to their transports.

In the panic, Caesar's craft was swamped by soldiers, forcing him to remove his armour and then swim to shore, holding his left hand above water to save some important documents.[14] The battle ended in defeat; although Pharos Island was still in Caesar's hands, the bridge was not. He had lost some eight hundred men (about half legionnaires and half sailors) but morale remained high and Caesar's men continued to repulse enemy attacks.[14]

Arrival of relief army

Soon after the skirmish for Pharos, a deputation arrived from the Alexandrians asking Caesar to exchange Arsinoe for Ptolemy XIII, claiming a general weariness with the despotic rule of Arsinoe and Ganymede.[14] Ptolemy XIII, feigning to fear being sent away, was released; he promptly joined his sister and urging his soldiers to continue the attack on Caesar.[14] Contemporaries viewed this in satirical terms, saying "Caesar's excessive kindness had made absurd by the deceit of a boy".[14]

The renewed assaults on Roman positions remained unsuccessful. The situation, however, began to turn in Caesar's favour when news reached him in March 47 BC of a relief force arriving overland from Syria under Mithridates of Pergamum at the head of an allied army which included a detachment three thousand Jews contributed by High Priest Hyrcanus II and led by Antipater, the father of Herod the Great.[15][14] The Jewish detachment encouraged the Jewish population of Alexandria to become more sympathetic to Caesar and after Mithridates' forces stormed Pelusium, Ptolemy XIII's forces redeployed east to contest Mithridates' crossing of the Nile.[16]


  1. ^ Tempest 2017, p. 62.
  2. ^ Tempest 2017, p. 63.
  3. ^ Goldsworthy 2006, p. 431.
  4. ^ Julius Caesar, Commentarii de Bello Civili iii. 104
  5. ^ Livy, Epit. 104
  6. ^ Cassius Dio xlii. 4
  7. ^ Beard 2015, p. 290.
  8. ^ Rawson 1992, p. 433.
  9. ^ Goldsworthy 2006, p. 433.
  10. ^ a b Goldsworthy 2006, p. 441.
  11. ^ Tempest 2017, p. 64.
  12. ^ Goldsworthy 2006, pp. 441–2.
  13. ^ a b c d e f Goldsworthy 2006, p. 442.
  14. ^ a b c d e f Goldsworthy 2006, p. 443.
  15. ^ Rawson 1992, p. 434.
  16. ^ Goldsworthy 2006, pp. 443–4.


  • Beard, Mary (2015). SPQR: a history of ancient Rome (1st ed.). New York. ISBN 978-0-87140-423-7. OCLC 902661394.
  • Goldsworthy, Adrian (2006). Caesar: Life of a Colossus. Yale University Press. ISBN 978-0-300-13919-8.
  • Rawson, Elizabeth (1992). "Caesar: Civil War and Dictatorship". Cambridge Ancient History. 9. ISBN 0-521-25603-8.
  • Tempest, Kathryn (2017). Brutus: the noble conspirator. New Haven. ISBN 978-0-300-18009-1. OCLC 982651923.