5. So upon the exhortations of Mucianus, and the other commanders, that he would accept of the empire, and upon that of the rest of the army, who cried out that they were willing to be led against all his opposers, he was in the first place intent upon gaining the dominion over Alexandria, as knowing that Egypt was of the greatest consequence, in order to obtain the entire government, because of its supplying of corn [to Rome]; which corn, if he could be master of, he hoped to dethrone Vitellius, supposing he should aim to keep the empire by force [for he would not be able to support himself, if the multitude at Rome should once be in want of food]; and because he was desirous to join the two legions that were at Alexandria to the other legions that were with him. He also considered with himself, that he should then have that country for a defense to himself against the uncertainty of fortune; for Egypt 23 is hard to be entered by land, and hath no good havens by sea. It hath on the west the dry deserts of Libya; and on the south Siene, that divides it from Ethiopia, as well as the cataracts of the Nile, that cannot be sailed over; and on the east the Red Sea extended as far as Coptus; and it is fortified on the north by the land that reaches to Syria, together with that called the Egyptian Sea, having no havens in it for ships. And thus is Egypt walled about on every side. Its length between Pelusium and Siene is two thousand furlongs, and the passage by sea from Plinthine to Pelusium is three thousand six hundred furlongs. Its river Nile is navigable as far as the city called Elephantine, the forenamed cataracts hindering ships from going any farther, The haven also of Alexandria is not entered by the mariners without difficulty, even in times of peace; for the passage inward is narrow, and full of rocks that lie under the water, which oblige the mariners to turn from a straight direction: its left side is blocked up by works made by men's hands on both sides; on its right side lies the island called Pharus, which is situated just before the entrance, and supports a very great tower, that affords the sight of a fire to such as sail within three hundred furlongs of it, that ships may cast anchor a great way off in the night time, by reason of the difficulty of sailing nearer. About this island are built very great piers, the handiwork of men, against which, when the sea dashes itself, and its waves are broken against those boundaries, the navigation becomes very troublesome, and the entrance through so narrow a passage is rendered dangerous; yet is the haven itself, when you are got into it, a very safe one, and of thirty furlongs in largeness; into which is brought what the country wants in order to its happiness, as also what abundance the country affords more than it wants itself is hence distributed into all the habitable earth.