The twin streams of Egypt’s history converge just below the Delta at Cairo, where the greatest city in the Islamic world sprawls across the Nile towards the Pyramids, those supreme monuments of antiquity. Every visitor to Egypt comes here, to reel at the Pyramids’ baleful mass and the seething immensity of Cairo, with its bazaars, mosques and Citadel and extraordinary Museum of Egyptian Antiquities. It’s impossible, too, not to find yourself carried away by the street life, where medieval trades and customs coexist with a modern, cosmopolitan mix of Arab, African and European influences. Egyptians have two names for the…