After the fall of Bilbeis the Muslims advanced to Babylon. It was the key city of Egypt. Close to it was Memphis the ancient capital of the Pharaohs. Modern Cairo is not far from what at one time was known as Babylon. The Muslims arrived before Babylon some time in May 640 A.D.
Babylon was a fortified city, and the Byzantines had prepared it for a siege. Outside the city, a ditch had been dug, and a large force was positioned in the area between the ditch and the city walls. The fort of Babylon was a massive structure 60 ft. high with walls more than 6 ft. thick. The fort was studded with numerous towers and bastions.
As soon as Amr arrived at Babylon he formed up his force of 4,000 men in assault formation and attacked the Byzantine positions in front of him it led to some hard fighting, and the attack was repulsed by the Byzantines. Amr pulled his men back and went into camp near the east bank of the Nile. The Byzantine force in Babylon was six times the strength of the Muslim force.
The Muslims launched attacks every now and then, but these were repulsed. For two months the confrontation wore on with the Byzantines sitting tight in their defences and repulsing the frequent Muslim attacks against the crossings of the ditch.
In July, Amr wrote to Umar asking for reinforcement. In August a reinforcement 4,000 strong came from Syria. Thus reinforced the Muslims renewed their attacks with greater force, but their attacks were not able to make any headway against Byzantine resistance. In these desultry fightings, a good number of Byzantine soldiers was killed, but no dents were made in the defences of the city. The attacks were called offend Amr again wrote to Umar for more belp.
Umar raised a force in Madina for despatch to Egypt. Among those who volunteered to fight on the Egyptian front was Zubeir bin Al-Awwam, a cousin of the Holy Prophet. Umar indeed offered Zubeir the chief command of Egypt. Zubeir did not accept the chief command, but he agreed to go to the help of Amr bin Al-Aas.
Reinforcement, 4000 strong was thus despatched from Madina to Egypt. It comprised four columns each column one thousand strong. These columns were commanded by Zubeir b. Al-Awwam; Miqdad bin Al-Aswad; Ubaida bin As-Samit, and Kharija bin Huzafa. Each Commander was in military prowess equal to a thousand men, and was the counterpart of Persian 'Hazer Mard' or gladiators.
This reinforcement arrived at Babylon sometime in September 640. The total strength of the Muslim force now rose to 12,000 and this was quite a modest strength. The Muslims now renewed their attacks against the Byzantines. In the attack launched by the Muslims some hard fighting followed, and some Byzantine detachments posted in front of the ditch were driven behind the ditch. The Byzantine defences, however, remained unshaken.
Ten miles from Babylon was Heliopolis. It was the city of the Sun Temple of the Pharaohs. There was the danger that some Byzantine force from Heliopolis might attack the Muslims from the flank while it was engaged with the Byzantine army at Babylon. With some detachments Amr and Zubeir marched to Heliopolis. There was a cavalry clash outside Heliopolis, and though many Byzantines were killed, the engagement was not decisive. At an unguarded point, Zubeir and some of his picked soldiers scaled the wall of the city, and after overpowering the guards opened the gates for the Muslim army to enter. Thereupon the local Byzantine garrison laid down their arms, and the city was occupied by the Muslims.
From Heliopolis Amr and Zubeir with their force returned to Babylon to press the siege against the Byzantines with greater force. The Byzantines now began to sally forth across the ditch and attack the Muslims. The Muslims invariably repulsed such attacks. The sallies increased in intensity and the Muslim counter charge also gained in intensity. It was a see-saw affair leading to a condition of stalemate with no side gaining a positive advantage.
To break this stalemate the Muslim high command approved a stratagem. The following day when the Byzantines launched the attack the Muslims fell back according to a determined plan. The Byzantines thought that they had overpowered the Muslims. They pressed the attack, and the Muslims continued to withdraw till the entire Byzantine army had crossed the ditch. At a signal of Amr, five hundred Muslim horsemen led by Kharija bin Huzafa broke cover and rode out in rear of the Byzantine army. The main Muslim army now turned back and charged the Byzantines with great violence. Reeling from Muslim blows the Byzantines moved back to be attacked in the rear by Kharija and his men.
The Byzantine forces were now thrown into confusion. Many Byzantines were killed, but the main Byzantine army managed to cross the ditch and seek shelter in the walled city. The Byzantines entered the city and shut the gates. The area between the ditch and the city came to be occupied by the Muslims and that was a tactical advantage. The Muslims brought some catapults into action and started hurling boulders inside the city. That caused considerable distress to the Byzantines locked up in the city. Maqauqas the Viceroy of Egypt and the High Priest of the Copts who had his headquarter in Babylon shifted his headquarter to the Isle of Rauda in the Nile which was a much safer place. The Byzantine General Theodorus remained in Babylon to conduct the operations.
From the Isle of Rauda, Maqauqas sent emissaries to the Muslim camp inviting negotiations. These emissaries remained in the Muslim camp for two days, and when they returned they were accompanied by some Muslim emissaries. The Muslim envoys saw Maqauqas, and they offered the Byzantines the usual three alternatives? Islam, Jizya? or arbitration by sword, Maqauqas wanted some time to consider the matter and the Muslim envoys returned.
Turning to his emissaries, Maqauqas asked as to what they had seen in the Muslim camp. The emissaries said: "We found a people to each of whom death is dearer than life, and humility dearer than pride. None of them has a desire or greed for this world." On hearing this Maqauqas thought that the Egyptians could not fight against such a people, and that the best course for them was to negotiate peace. He accordingly asked Amr to send another delegation for negotiating peace.
Amr accordingly sent a delegation of ten picked warriors led by Ubada bin As Samit. All of them were over six feet tall and Ubada was the giant of a man being about seven feet tall. Maqauqas talked long of the might of the Byzantine empire. He said that Heraclius would be sending a very large force, and the Muslims could not be a match for the Byzantine force. He stressed that the best course for the Muslims was to withdraw from Egypt. He said that he would give as a gift an amount of two diners to each soldier, an amount of 100 diners to each Commander, and one thousand diners to the Caliph.
Ubada made Maqauqas understand that the Muslims could not be frightened by the strength of the enemy, nor could they be bought with gold. They were fighting in the name of Allah, and if they won they would have all they wanted; if they died they would get paradise. Ubada offered the usual three alternatives, Islam, Jizya, and sword. Maqauqas enquired whether a fourth alternative was possible, and Ubada said "No". Maqauqas consulted his men. He wanted them to accept the offer of Jizya, but they did not agree. Under the advice of his counsellers, Maqauqas repeated his offer of diners, and doubled the amount. The Muslims rejected the offer contemptuously. Thereupon the negotiations broke down and the Muslim envoys returned from the Isle of Rauda.
In Babylon itself there was a round of negotiations between Theodorus the Byzantine Commander and Amr b. Al-Aas. Amr himself went to Theodorus to have the matter talked over. Theodorus adopted a patronising attitude and wanted the Muslims to retire after receiving a few diners each. The offer was brushed aside by Amr, and when the usual three alternatives were offered to Theodorus he said that the Byzantines knew how to wield their swords. When the negotiations broke down, and Amr was to return, Theodorus said in a boastful mood: "You have entered, now see how you get out." Theodorus sent word to the guard at the gate that as Amr would cross the gate, something should fall on him to crush him. Amr shrewd as he was sensed the danger. At the time of parting handshake with Theodorus Amr said, "I go but I will return with some of my senior colleagues so that you may talk to them as you have talked to me, and let us hope we may reach a decision acceptable to both the parties." Theodorus look these words at their face value and he came personally to the gate to see off the Commander-in-Chief of the Muslim forces.
Theodor us waited in vain for another visit of Amr and his companions. Amr said that he would visit Babylon again but that would be as a victor after the city had been conquered. The siege of Babylon had begun in May and it had dragged on till December. The Muslims now became very much concerned at the delay in capturing the city. Zubeir had a reconnaissance of the city and he came across a point which was unguarded. On the 20th of December when it was a moonless night, Zubeir and some soldiers accompanying him managed to scale the wall. Then they rushed to the gate and killing the guards opened the gate for the Muslim army to enter. The Muslim army rushed inside the city. Some resistance was offered which was soon overcome. When it was day it was found that Theodorus and his army had slipped away to the Isle of Rauda by the river route. The city of Babylon was captured by the Muslims on 21st December 640.
On the 22nd December, Maqauqas entered into a treaty with the Muslims. By the treaty, Muslim suzerainty over the whole of Egypt was recognised, and the Egyptians agreed to pay Jizya at the rate of 2 diners per male adult. The treaty was subject to the approval of the emperor Heraclius, but Maqauqas stipulated that even if the emperor repudiated the treaty, he and the Copts of whom he was the High Priest would honour the terms of the treaty, recognise the supremacy of the Muslims and pay them Jizya.
Maqauqas submitted a report to Heraclius and asked for his approval to the terms of the treaty. He also offered reasons in justification of the acceptance of the terms of the treaty.
Amr b. Al-Aas submitted a detailed report to Umar and asked for his further instructions.