The Eastern Roman Empire had become the Greek speaking Byzantine Empire, with its capital moved from Nicomedia to Constantinople in 324 AD by Emperor Constantine. The Byzantine and Sassanian Empires had dominated the Middle East, and the local tribes had suffered great misery from the wars between these two. Together with this, many Christian faiths had been persecuted as heretic by the Orthodox Christians and were ejected to adjacent countries. There was a general willingness amongst them to shed their existing oppressors for another, potentially better. This led to the Islamic Empire growing at a phenomenal rate under Umar. Syria and Iraq were overrun in 636-7 AD and within 10 years the Muslim army had conquered Mesopotamia and Persia, causing the collapse of the Sassanian Empire in 642 AD, and the withdrawal of their elite eastwards. The Muslims overran Egypt, previously part of the Byzantine Empire, by crossing the Sinai in 639 AD, and capturing Alexandria in 641 AD. Armenia was also annexed.

Some religions tended to destroy any technology associated with a different religion they came across, whereas the Muslims were very keen to absorb the knowledge of other faiths, as long as it did not directly contravene their theology. A great deal of Greek and Roman knowledge and technology was captured in the taking of Alexandria, as the library still contained several hundred thousand scrolls and books stored there by the Romans and the Greeks before them. There are various versions of what happened subsequently, but the most probable was that Caliph Umar had those considered heretic destroyed, but the rest preserved for translation, which took place over the next 200 years. Also the Egyptians were allowed to continue Coptic religious rituals.

9.48 North Africa

The Berber Nation had inhabited North Africa from before 3,000 BC, and the people were known generally as Libu (Libyans). They were subjected to the influence of a number of invaders starting with the Phoenicians who settled Carthage possibly in 814 BC and created several other North African maritime colonies. After the Punic wars the Romans took control and immigrant Romans developed large agricultural estates providing huge quantities of food for their Empire. Then the Vandals took advantage of the fall of the Western Roman Empire to migrate from Eastern Europe through Gaul (France), Spain, across to North Africa at Gibraltar and onwards to Carthage. However by 534 AD the Byzantines had recaptured North Africa and by 565 AD the Byzantine Empire included Italy, Greece, Anatolia, The Levant, Egypt, parts of North Africa and part of Southern Spain.

From 642 AD the Arabs made further inroads into North Africa from Egypt, under the third Caliph Uthman (644-656 AD) and the fourth Caliph Ali (656-661 AD). The choice of Ali as Caliph was contested and eventually led to the split between the Sunni and Shiite Muslims.