In 1548, under the Florentine lordship of the Medici, Charles V gave Cosimo I de Medici the task of defending the territories of Elba and the commercial traffic of the Tyrrhenian Sea. The Duke, who strongly believed in the potential of the island and wanted to transform it into the center of Florentine rule over the Tyrrhenian, decided to fortify the ancient city of Ferraia, the current Portoferraio. A real jewel of military town planning that took the name of Cosmopolis was born by the architect Giovanni Battista Bellucci and by the engineer Giovanni Camerini. Thanks to its natural conformation, the gulf of Portoferraio protected on one side a strip of land that closes the port like a spiral, and on the other hand protected by two rocky headlands overlooking the sea, was extremely strategic and suitable for defense. Fort Stella and Fort Falcone were built in the upper part of the promontory and the Linguella tower, near the dock, all connected by a bastion wall. Later the defense was further strengthened by walls and ramparts also on the land front side according to the project of the architect Bernardo Buontalenti, transforming the city into an impregnable fortress, as well as a safe naval base.

The study of urban representations of the city testifies to how the foundation of Cosmopolis for the Medici duchy was an event of extraordinary value, symbol of the strength of the Duke and his expansive abilities, symbol of an ideal city not only conceived and designed in contemporary treatises, but actually made.