If you have not yet entered Egypt, return from it. But if you reach it, or any part of its land, then proceed, for I will support you." Marwa turned to those around him, saying, "Where are we, O people?" They replied, "In the land of Egypt." He said, "Then let us cross with the help of God Almighty." And so Amr ibn al-'As entered Egypt with four thousand men in the eighteenth year of the Hijra, and they made their treasury in its eastern division. The number of men increased daily as they were joined by the Bedouin tribes they encountered on their way. After a month, the first place where they fought the Romans was a fierce battle near... Victory came to the Muslims, and Abdullah ibn Sa'd was on the right wing of Marwa from the time he set out from Caesarea until he finished his war. Then Marwa advanced, fighting only with the utmost determination, until he reached Bilbeis, where they fought him for about a month until God granted him victory. In Bilbeis was Armanusah, the ruler of the Copts appointed by the Romans. Amr wished to appease Al-Muqawqis to win his favor, so he sent him his daughter Makrama with a gift. Her father was greatly pleased by her arrival. Then Amr marched on until he reached the Mokattam mountain, overlooking Babylon, which stood on the eastern bank of the Nile, opposite the Great Pyramids. It was a strong and ancient fortress, to its east the Mokattam mountain, and on its face were wrinkles indicating its antiquity. Between the mountain and the fortress was a piece of land with no signs of civilization except for some monasteries and churches. Then he looked to the west, and there was the Nile flowing in front of it, increasing its impregnability. To the west of the Nile was land covered by nature with a green cloak of fertile grass and trees. And on the island of Rawdah, which was known as the Island of Egypt, water surrounded it all year round. The Nile separated the fortress from this island by a wooden bridge, and similarly between it and Giza. People and animals crossed over them from the eastern bank to the island, and from there to the western bank. These two bridges were made of boats placed side by side, fastened with iron chains, and on top of the boats were planks. The width of each bridge was three cubits. Amr looked beyond the island and saw the Great Pyramids, firm as mountains. Some historians of the time attribute the fortress to Babylon or the Gate of Babylon. Historians differ on this. It appears that it was a fortress built by the Persians when they ruled Egypt and named it after their capital, Babylon, because it was in their possession.