Cosimo I de' Medici, Grand Duke of Tuscany
It was founded by Cosimo I de' Medici, Grand Duke of Tuscany, in 1548, with the name of "Cosmopoli" ("Cosimo's City"), to balance the presence of the Spanish citadel in Porto Azzurro. It had three forts (Forte Stella, Forte Falcone and Forte Inglese) and a massive line of walls, all still visible today.