First, I'd like to write that Leo Africanus (Hasan) was an actual person who lived during the dates that the author Maalouf describes (1490...). Leo Africanus also wrote, in the shadow of Arab Ibn Batutta, his Description of Africa. And just as Maalouf illustrates, Leo Africanus was a merchant and diplomat. That said, I think it is nice to know that Maalouf didn't just make up a character (possibly for his own agenda, such as a revisionist-history, which it is not), rather Leo Africanus was actually a real global citizen.
After his their escape from Granada due to the Spanish Reconquest, Hasan and his family make their way to Fez (now called Fes, the third largest city in Morocco). Fez was once (around 1100s) one of the largest cities before Hasan's time, it was still a thriving center for trade and international commerce when Hasan's family settled there. Hasan's (Maalouf's) descriptions of the city add to this international image. Almost every Fezian's occupation is related to commerce in some way. Many women are involved in the marketplace, most of the men are merchants; for example, Hasan's father is called the "weigh master", Hasan's friend Harun is (or was, depending on how far in the book you are) involved in a trading guild. Later on, Hasan himself will leave behind his university studies and become a influential merchant, traveling to Timbuktu, Cairo, Constantinople, among other places.
Timbuktu, which was a very isolated city in the opinions of Europeans (this is why "Timbuktu" is sometimes used to describe someplace far away), was actually another center (albeit not central) city for international trade. Cairo and Constantinople were of course heavyweights in the global society as well (Constantinople was even one of the world's largest cities around 1600).
However, we get the picture that these cities, and the Islamic civilization in northern Africa in general, were in a period of decline. This might have been caused by the growing friction between Europe. Did these once-great Islamic cities--centers of international trade--turn against one-another and hasten defeat?