Conquest of Egypt
Before the message of Islam reached Egypt, it had been conquered by the Persian Empire under Khosrau II in 616 AD. But however, Emperor Heraclius recaptured it after a sequence of campaigns against the Sassanid Persians. Before the message of Islam reached them, majority of them were Coptic Christians or Jews.
The first migration of Muslim to Africa was in Abyssinia (modern day Ethiopia). When the Muslims were persecuted in Makkah the Prophet told them to migrate there. In that area Abyssinia was ruled by a Christian king named Al-Najashi who welcomed them to stay, and according to Seerat Ibn Hisam he ended up converting to Islam.
Later on in time the Byzantines lost Sham (greater Syria) and the Ghassanid Kingdom to the Muslims. The Christians and Jews living in that area were not pleased with the Romans, so they wanted liberation. But in December 639, . In the seventh century, Islam entered Africa from the northeast corner. The second caliph Umar Ibn al-Khattab, made, Amr Ibn al-As his general to lead twelve thousand soldiers across what is now the Red Sea and conquered the city of Fustat (modern day Cairo).
Most of the soldiers belonged to Arab tribes but also had some Roman and Persian converts to Islam. On Eid al-Adha, the Muslim army marched from Shajratein to Al Arish, a small town. The town put up no resistance, and the citizens offered bayah (allegiance) on the usual terms according to Islam. The Muslim soldiers celebrated Eid there. Under Umar’s caliphate, he established military strongholds in towns and Fustat was of the first.
fAfter seizing the former Roman conquered cities of Cairo, Constantinople, Alexandria, and Tripoli, geologically strategic Egypt mandated military movements to the west along the hazardous Mediterranean shores. Gradually, Muslim armies rode south, along the White Nile (a river off the Nile in Egypt) conquering all of Egypt.