In spite of the title, Leo's work is not a comprehensive description of the entire African continent. There is no mention, for example, of Christian Ethiopia or of the lands to the south of the Sudanic zone, which already were familiar to European readers from contemporary Portuguese and Italian reports. As mentioned above, Alvise Cadamosto's description of his voyages to West Africa was first published in Italy in 1507. The first volume ") of the "Asia" by João de Barros, which describes the advance of Portuguese discoveries on African coasts until 1498 with extensive accounts of Gold Coast, Benin, and the kingdom of Congo, was published in Portugal in 1552. "The Prester John of the Indies" by Francisco Alvares, providing an accurate description of Ethiopia, was published in Portugal in 1540.
The emphasis in Leo's work is, understandably, on Morocco: the description of Fez alone takes as much space as the two entire books reserved for Tunisia and Libya. Even if the author's primary focus is geographical, an historical aspect is always present, albeit sometimes superficially, as most passages contain at least one or two historical anecdotes related to the respective area. As to the composition and approach, Leo's work represents the traditional literary genre of "the routes and the realms" which was famoured by medieval Arab geographers and historians, such as Ibn Hawqal, al-Bakri, and al-Umari, whose works Leo used as sources for his own work. Hence we may characterize Leo's "Description of Africa" as the final contribution of Islamic learning to Western civilization, in the sense that it offered new, hitherto unknown knowledge to Western scholars; the end of the cultural exchange which had begun in the eleventh-century Spain and Sicily. On the other hand, Leo's work was by no means unique to his readers. Similar approach was used by many Renaissance scholars, who considered geography, ethnography, and history inseparable subjects.
Leo's knowledge was above all based on his own experiences and observations. I have already referred above to his great voyages which are supposed to have taken him almost everywhere in the Islamic Mediterranean, from southern Morocco to Arabia, and across the Sahara. The question whether these voyages represent events that really took place or whether they are just a literary invention by a cunning captive who wanted to impress his patron has some relevance when we are estimating Leo's reliability as an historical source from the point of view of modern historiography. Considering, however, his repution and influence on the development of European geography of Africa, the question is less meaningful. Until the early nineteenth century, Leo's European readers were not capable of distinguishing facts from fiction in his text, any more than medieval readers had been able to separate reality from imagination in Marco Polo's "Travels". This concerns particularly Leo's description of the city of Timbuktu, which he depicts as an African version of Zipangu.
Towards the end of October, the brother of the bishop of Salamanca, a Spaniard and a Captain, captured on the sea a Turkish ambassador whom the Grand Turk had dispatched to the king of Tunis on the Barbary Coast. The man was taken to Rome with twelve other captives and placed in the house of the above mentioned bishop at Sant'Agostino in Rome, where the Cardinal of Nantes had once lived. Then the said ambassador was taken to the Sant'Angelo.