Many of the Jews who’d fled Byzantine Emperor Heraclius in 628 CE when he massacred the people of Jerusalem fled to Egypt. This was also part of the Empire and the Coptic Christians there had some longstanding tensions with the Hebrew peoples. In 617 CE Jewish residents of Alexandria had sided with Persian invaders, and the Copts weren’t keen on more Jews moving in. Jews had lived in Alexandria since its founding in 332 BCE under Alexander the Great.
Starting in those early BCE years Alexandria Jews in Egypt translated the Torah into Greek. This Old Testament, LLX or Septuagint (Seventy), was the one read by the Apostle Paul and is the foundation of many modern Christian Bible translations, including the Greek Orthodox Bible. Over the time of this translation, the population of Alexandria was Christianizing, as were the translators. LLX was completed in 132 BCE. Twelve years after the influx of Jerusalem Jews, Arabs took Egypt for the Caliphate and not much is known about life for Egyptian Jews.
North African tribes who spoke the Berber language converted to Judaism from the 1st to 7th centuries. They were fabled to be the descendants of Goliath, the Biblical Giant from Canaan. When the Arab conquest began to sweep through Africa, many Christian Berbers converted to Islam, but most Jewish Berbers did not. They had faith in their God, and in their Queen. Queen La Kahina Dahiya ruled over a nomadic Jewish territory spreading from modern Tunisia to Morocco and gave the Muslims their only serious defeat in the Islamic campaigns, forcing the Arabs to retreat all the way back hundreds of miles to Egypt.
According to Arab historians, in 698 CE the Kahina (Prophetess) called a war council of Bedouins (nomads) and blamed the attack on fruits of the city. Under her supposed orders, buildings were torn down, gems were buried, and fruit orchards and fields were set alight to make the city less desirable. When the Muslims came back with reinforcements, they were greeted by the common people as liberators – according to the victors who wrote this history.
Once Dahiya knew defeat was certain, she told her sons to surrender themselves and convert; Islam was still monotheism to the one true God after all. For herself, she chose honorable death in battle. (Though one history by Irving Washington has her taken captive and beheaded when she refuses to convert.) One of Kahina Dahiya’s sons went on to win victory over Visigothic Spain on behalf of his new Muslim masters in 701 CE.