In 1590, Grand Duke Ferdinando I commissioned the architect Bernardo Buontalenti to build a majestic fortress to celebrate his power. It was important to be able to watch over the area of Florence called Oltrarno, from above, and guarantee a safe refuge for the Grand Duke if there were any uprisings in the city. The architect Buontalenti built a modern fortification in five years and was also helped and inspired by Antonio da Sangallo the Younger's designs for the fortifications of Castro, in Lazio. The chosen location had already been identified as a strategic site by Michelangelo in 1529. At that time, he was chief engineer of the fortifications and was called upon to reinforce the city walls during the siege of Florence.
The first version of the Forte Belvedere can be admired in a fresco by Vasari in the Studiolo di Clement VII (Pope Clement VII's small study) in Palazzo Vecchio . The Fort may also have been the chosen place for safeguarding the Medici treasure room. Ingenious mechanisms had been activated for its protection, the harquebuses were ready to shoot at any thieves and a trapdoor contained a lethal deadfall: sharp blades had been placed at the bottom. After its occupation by Grand Duke Pietro Leopoldo, the Forte Belvedere was opened to the Florentines as a place for viewing the city of Florence. The cannons fired blanks announcing midday and this led to the Florentines calling it "the cannon of the pasta".