In July 1324, Sultan Musa of Mali rocked up in Cairo, together with an entourage of over ten thousand slaves and retainers, staying as the guest of the city’s Mamluk governor as he passed through Egypt on the hajj. Fifty years later Cairenes were still talking about it. The Malian ruler flooded the city with gold. Sultan Musa left no Mamluk official or humble petitioner empty-handed, gifting and spending so lavishly that the price of gold collapsed on the Cairo market. His Mamluk host was left full of anecdotes from their conversations: of the magnificence of the Mali kingdom, so vast that it took three years to traverse by foot, and of the fantastic exploits of its royal house, which had sent vast armadas to cross the Atlantic. The brilliance of this African sovereign is thought to have led the Majorcan Jewish cartographers who made the Catalan Atlas in 1375 to place at the centre of the trade routes crossing the Sahara an image of a black king seated on a golden throne and holding up an enormous nugget of gold.
By the time of Musa’s visit, Cairo had been at the heart of a network of African diplomatic exchange for over half a millennium. Its Muslim governors had for a long time been obliged to deal with the continent’s great Christian sovereigns, and here relations could be testy. In 758, Egypt’s Abbasid governor sent a papyrus démarche to the neighbouring king of Nubia (in present-day Sudan), demanding that he respect the terms of their bilateral treaty, stop harassing travelling Egyptian merchants and send slaves of good quality in the annual tribute rather than the ‘handful of old men and one-eyed people’ he had dispatched to date. The Nubian sovereign’s reply has not survived, but we may suppose that he complied. For more than six centuries – as Islam was being carried from Egypt to China – this treaty shielded Christian Nubia from holy war.