As illustration only : The Nile from Idrissi.
Annon. (Katib Marrakesh): Kitab al-istibsar fi ajaib al-amsar
(Foresight in the wonders of the regions) (12th)
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The author of the work: Kitab al-istibsar fi ajaib al-amsar is unknow; a reviser (nazir) finished his job on the earlier work in 1191AD. It seems it is mainly an adaptation from al Bakri’s work (1068) for North and West Africa. As to East Africa only the sources of the Nile are mentioned.
Taken from: برنامج المكتبة الشاملة - http://www.shamela.ws
P45
The wonders of the land of Egypt.
Egypt first country in the Region IV, her zodiac Gemini, and Mercury. It is from Aswan (1) to Alexandria, and fertilized and planted too and irrigated by the Nile all. The Nile is among the wonders of the world but one does not know its source from the mountains of the moon, behind the equator nine and a half degrees, out of the 12 sources there, who meet in the two lakes called Kalptaih, then emitted from each three rivers, including the Nile Egypt and other rivers that will be mentioned, God willing. And in the South of the country in which because of the burning heat there is not a plant or an animal, to the proximity of the sun from that position.
The Nile said to emit in the sands of Egypt and the mountains, and then penetrates the ground in Sudan, which follows the country Zinj, then(a branch) emits in a bay in the country of the Zinj in the Sea of Zinj.
It is the high waters of this arm that feed the floods of the Nile of Egypt. There is the crocodile called waral (lizard) that exists in the Nile of Egypt and lives in the desert and grazing lands. It is of the race of crocodiles because when the crocodile comes out of the Nile to cross the banks, it sometimes happens that the water withdraws and that it remains on the ground; it is then that it multiplies and becomes the waral well known. The crocodile is found only in the Nile of Egypt or in a river coming of the same source.
P73
Moreover, the practical king of the Levant defeated the Kingdom of Egypt, and his name was Al-Walid Ibn Dumaa (2), and the origin of these giants was from among the Arabs, and he was extremely powerful and wiped out the nations and brought the countries in subjugation until he reached what is called the Mountain of the Moon under which the Nile emanates. Never before was the equator reached , and also reaching the temple of the sun and the land of gold, which is a land that sprouts bars of gold, and this Coptic king enslaved and ruled for 120 years and then perished.
(1)Aswan: southern border town on the Nile in Egypt.
(2) Al-Walid: Ar-Rayyan ibn al-Walid ibn Dauma was an Amalekite king of Misr during the time of Prophet Yusuf (=Joseph)
Walid is mentioned in the following books: Al-Mas'udi: (916) Kitab al-Ausat; Ibn Babawayh (991); Maslamah ibn Ahmad Majriti (1050); Katib Marrakesh (12th); Wasif Shah (1209); Ibn al-Dawadari (1335); Nuwayri (1333); Maqrizi (1441) (Oualid); Ibn Abd'essalem al-Menoufi (15th); Suyuti (1505).