Strabo Geography 17.1.5

[5] The ancients understood more by conjecture than otherwise, but persons in later times learnt by experience as eyewitnesses, that the Nile owes its rise to summer rains, which fall in great abundance in Upper Ethiopia, particularly in the most distant mountains. On the rains ceasing, the fulness of the river gradually subsides. This was particularly observed by those who navigated the Arabian Gulf on their way to the Cinnamon country, and by those who were sent out to hunt elephants, or for such other purposes as induced the Ptolemies, kings of Egypt, to despatch persons in that direction. These sovereigns had directed their attention to objects of this kind, particularly Ptolemy surnamed Philadelphus, who was a lover of science, and on account of bodily infirmities always in search of some new diversion and amusement. But the ancient kings paid little attention to such inquiries, although both they and the priests, with whom they passed the greater part of their lives, professed to be devoted to the study of philosophy. Their ignorance therefore is more surprising, both on this account and because Sesostris had traversed the whole of Ethiopia as far as the Cinnamon country, of which expedition monuments exist even to the present day, such as pillars and inscriptions. Cambyses also, when he was in possession of Egypt, had advanced with the Egyptians as far even as Meroë; and it is said that he gave this name both to the island and to the city, because his sister, or according to some writers his wife, Meroë died there. For this reason therefore he conferred the appellation on the island, and in honour of a woman. It is surprising how, with such opportunities of obtaining information, the history of these rains should not have been clearly known to persons living in those times, especially as the priests registered with the greatest diligence in the sacred books all extraordinary facts, and preserved records of everything which seemed to contribute to an increase of knowledge. And, if this had been the case, would it be necessary to inquire what is even still a question, what can possibly be the reason why rain falls in summer, and not in winter, in the most southerly parts of the country, but not in the Thebaïs, nor in the country about Syene ? nor should we have to examine whether the rise of the water of the Nile is occasioned by rains, nor require such evidence for these facts as Poseidonius adduces. For he says, that Callisthenes asserts that the cause of the rise of the river is the rain of summer. This he borrows from Aristotle, who borrowed it from Thrasyalces the Thasian (one of the ancient writers on physics), Thrasyalces from some other person, and he from Homer, who calls the Nile heaven-descended: But I quit this subject, since it has been discussed by many writers, among whom it will be sufficient to specify two, who have (each) composed in our times a treatise on the Nile, Eudorus and Aristo the Peripatetic philosopher. [They differ little from each other] except in the order and disposition of the works, for the phraseology and execution is the same in both writers. (I can speak with some confidence in this matter), for when at a loss (for manuscripts) for the purpose of comparison and copy, I collated both authors. ² But which of them surreptitiously substituted the other’s account as his own, we may go to the temple of Ammon to be informed. Eudorus accused Aristo, but the style is more like that of Aristo.

The ancients gave the name of Egypt to that country only which was inhabited and watered by the Nile, and the extent they assigned to it was from the neighbourhood of Syene to the sea. But later writers, to the present time, have included on the eastern side almost all the tract between the Arabian Gulf and the Nile (the Aethiopians however do not make much use of the Red Sea); on the western side, the tract extending to the Auases and the parts of the sea-coast from the Canobic mouth of the Nile to Catabathmus, and the kingdom of Cyrenaea. For the kings who succeeded the race of the Ptolemies had acquired so much power, that they became masters of Cyrenaea, and even joined Cyprus to Egypt. The Romans, who succeeded to their dominions, separated Egypt, and confined it within the old limits.

The Egyptians give the name of Auases (Oases) to certain inhabited tracts, which are surrounded by extensive deserts, and appear like islands in the sea. They are frequently met with in Libya, and there are three contiguous to Egypt, and dependent upon it.

This is the account which we have to give of Egypt in general and summarily. I shall now describe the separate parts of the country and their advantages.