The Suez Isthmus is the main route through which Arab tribes flowed towards the Nile Valley. However, the entry of Arabs into Sudan before Islam had profound effects, as their presence was most likely confined to the eastern part and they added nothing new to life in that region, neither culturally nor in terms of changing the anthropological and ethnic characteristics of the local population. But this passage had a human importance with its gravity, as it was the only land route connecting the two parts of the Arab Islamic homeland in Asia and Africa. Through this route, Arab tribes populated Egypt, Sudan, and the Nile Valley, and in their advance, they reached the center of the continent via these desert routes and paths. Therefore, it can be said that the Suez Isthmus is considered the most important route taken by successive human groups, as mentioned in the Holy Quran and the Book of Genesis, where these human waves traversed it in close or distant periods, depending on the source to which each group refers, and according to their migratory density or scarcity. There is no doubt that these migrations and human movements from Asia had the greatest impact on the settlement of Africa. There is also no doubt that the Arab migrations preceding the advent of the light of Islam paved the way for the entry of Islam into Africa, just as they prepared for the Arab conquest of Egypt. The prevailing agreement among ethnologists is that these ancient migrations came through the three passages, the most important of which is the Sinai passage, and then settled in Egypt, eastern Sudan, and the center of the continent, where the Himyarite migration occurred about two centuries before Christianity, after the collapse of the Marib Dam. 18