Circa 1500, a magnificent book of nautical instructions, called Description des côtes, des îles et des ports de l’Océan atlantique et de la mer Méditerranée, was offered to the young prince François d’Angoulême (then king François Ier). This anonymous manuscript contains a French translation of the Compasso da navegare, a famous portolan text of the 13th c., and some passages of the Liber Insularum of Cristoforo Buondelmonti, illustrated with maps of the coasts and of the islands of the Mediterranean Sea. The purpose of such a beautifully illuminated book regarding technical matters is replaced in the context of the education of the prince and the maritime policy in France in the age of geographical discoveries. Then, the artistic style of the book is compared to another magnificent manuscript of the same period, displaying maps, the Insularium Illustratum by Henricus Martellus, kept in the library of the Condé Museum, Chantilly.